Sarcoma
Soft tissue sarcoma, GIST, desmoid, and retroperitoneal sarcoma
Clinical FeaturesClick to collapse
Typical Presentation
Soft tissue sarcomas (STS) most commonly present as a painless, enlarging mass located in the extremities (43% of cases), trunk (10%), visceral organs (19%), retroperitoneum (15%), or head and neck (9%) [EXTSARC-1, MS-2]. The differential diagnosis includes benign lesions such as lipomas, desmoid tumors, and other malignant entities. Retroperitoneal/intra-abdominal STS often present insidiously with abdominal fullness, pain, or incidental findings on imaging [RETSARC-1]. Desmoid tumors (aggressive fibromatosis) present as firm, often painless, locally invasive masses that rarely metastasize, with a tendency for local recurrence; they may occur in the abdominal wall, intra-abdominal mesentery, extremities, or chest wall [DESM-1, MS-30]. Rhabdomyosarcoma (RMS) in adults most commonly arises in the extremities (26%), trunk (23%), genitourinary tract (17%), and head and neck (9%) and can present as a rapidly growing mass [RMS-1, MS-34]. Pleomorphic RMS is rare and behaves like high-grade STS. In children and adolescents, RMS is the most common STS, with embryonal and alveolar histologies. Atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDLPS) of the extremity, trunk, or abdominal wall presents as a slow-growing, deep-seated mass; retroperitoneal WDLPS may be found incidentally [ALT/WDLPS-1]. Borderline and malignant phyllodes tumors of the breast present as rapidly enlarging breast masses, often with skin changes, and require differentiation from breast carcinoma [PHYLLSARC-1, PHYLLSARC-2].
Symptoms
Palpable mass
The most common presenting symptom is a painless, enlarging soft tissue mass. In retroperitoneal sarcomas, the mass may not be palpable until large, with symptoms of abdominal discomfort, early satiety, or back pain.
Pain
Pain may be present if the tumor compresses or invades nerves, bone, or adjacent structures. Pain is more common in high-grade lesions and in retroperitoneal sarcomas.
Functional impairment
Extremity sarcomas may cause limited range of motion, neurological symptoms (numbness, weakness), or vascular compromise if located near neurovascular bundles.
Systemic symptoms
Rarely, large retroperitoneal or visceral sarcomas may cause weight loss, anorexia, or fatigue. Advanced/metastatic disease may produce cough, dyspnea (lung metastases), or abdominal pain (liver metastases).
Breast mass (phyllodes tumor)
Phyllodes tumors present as a firm, painless breast mass that can grow rapidly. Malignant phyllodes may cause skin ulceration or chest wall invasion.
Signs
Palpable mass on physical exam
Firm, often fixed to underlying structures, may be tender. Superficial masses are more easily detected; deep-seated retroperitoneal masses may require imaging for detection.
Neurologic deficits
Motor weakness, sensory loss, or reflex changes may be present if the tumor involves major nerves (e.g., sciatic nerve in thigh sarcomas).
Vascular compromise
Edema, pallor, or diminished pulses can occur with compression or invasion of major vessels.
Abdominal mass or organomegaly
Retroperitoneal sarcomas may present with a palpable abdominal mass on deep palpation. Hepatomegaly or splenomegaly may be seen with metastatic disease.
Breast changes (phyllodes)
Firm, well-circumscribed breast mass; may have overlying skin dimpling or ulceration. Nipple discharge is rare.
Red FlagsClick to collapse
Rapidly enlarging soft tissue mass over weeks to months
Mass with new onset of pain, especially at rest or at night
Neurological deficit (motor weakness, sensory loss) associated with a mass
Acute vascular compromise (pallor, pulselessness, cool extremity) with a mass
Unexplained systemic symptoms (weight loss, fever, night sweats) in the setting of a soft tissue mass
Breast mass with rapid growth, skin changes, or size >5 cm (suspicious for malignant phyllodes)
Intra-abdominal mass causing obstructive symptoms or ascites
Previous radiation therapy to the area
Personal or family history of Li-Fraumeni syndrome, neurofibromatosis, familial adenomatous polyposis (FAP), or hereditary retinoblastoma
Fungating, necrotic, bleeding, or superinfected tumor (may preclude preoperative radiation/chemotherapy) [EXTSARC-3A footnote t]
InvestigationsClick to collapse
Diagnostic
History and physical examination (H&P)
Essential for baseline assessment, detection of mass characteristics, and identification of hereditary syndromes.
Cross-sectional imaging of primary tumor
Provides details about tumor size, depth, relationship to neurovascular structures and adjacent organs.
Core needle biopsy (preferred) or incisional biopsy
Establishes malignancy, histologic subtype, and grade. Image-guided core needle biopsy is preferred for deep-seated tumors.
Ancillary diagnostic techniques (IHC, cytogenetics, molecular testing)
Necessary for definitive diagnosis when morphology is equivocal; many STS subtypes harbor characteristic genetic aberrations.
FDG-PET imaging (CT or MRI)
Useful in staging, prognostication, grading, and determining response to neoadjuvant chemotherapy.
Plain radiographs
May be warranted in selected circumstances (e.g., to evaluate bone involvement or for long-term surveillance to minimize radiation).
CT angiogram
Useful for surgical planning when major vascular involvement is suspected.
Staging
Chest imaging (CT chest without contrast preferred, or plain radiographs)
Essential to evaluate for pulmonary metastases, which is the most common site of distant spread for most STS subtypes.
CT abdomen/pelvis with contrast (or MRI)
Necessary for retroperitoneal/intra-abdominal STS; also indicated for specific histologies with propensity for abdominal/pelvic metastases (e.g., myxoid/round cell liposarcoma, LMS, epithelioid sarcoma).
MRI brain with and without contrast (or CT brain if MRI contraindicated)
To evaluate for CNS metastases in histologies with high propensity for brain spread.
Total spine MRI
Myxoid/round cell liposarcoma has a higher risk of spine metastases.
Whole body MRI or FDG-PET imaging (CT or MRI)
To identify soft tissue metastases or bone metastases in histologies with unusual metastatic patterns.
Regional lymph node assessment (CT, FDG-PET, or sentinel node biopsy)
Certain histologies have a propensity for nodal metastases (e.g., clear cell sarcoma, angiosarcoma, epithelioid sarcoma, alveolar RMS). Sentinel node staging can be considered in select cases.
Bone scan (99mTc-MDP)
To evaluate for bone metastases in histologies with skeletal tropism.
Breast MRI with and without contrast
Required for staging and surgical planning in phyllodes tumors; also for surveillance.
Biomarkers
NTRK gene fusion testing (NGS or FISH)
Identifies patients with NTRK fusion-positive sarcomas who may benefit from TRK inhibitors (larotrectinib, entrectinib, repotrectinib).
Tumor mutational burden (TMB) testing (≥10 mutations/megabase)
Pembrolizumab is approved for TMB-H solid tumors that have progressed and have no satisfactory alternative.
Microsatellite instability (MSI)/mismatch repair (MMR) testing
Pembrolizumab is approved for MSI-H or dMMR tumors.
ALK translocation testing (by IHC, FISH, or NGS)
Identifies inflammatory myofibroblastic tumor (IMT) with ALK translocation, which is responsive to ALK inhibitors (alectinib, brigatinib, ceritinib, crizotinib, lorlatinib).
MDM2 and CDK4 amplification (by FISH or NGS)
Confirms diagnosis of well-differentiated/dedifferentiated liposarcoma and identifies potential CDK4 inhibitor candidates (palbociclib, abemaciclib).
CTNNB1 or APC mutation testing
Sporadic desmoid tumors often have CTNNB1 mutations; APC mutations indicate FAP/Gardner syndrome.
RET gene fusion testing (NGS)
Selpercatinib is active in RET fusion-positive solid tumors, including sarcoma.
HLA-A*02:01/02/03/06 and MAGE-A4 expression
Afamitresgene autoleucel (T-cell therapy) is approved for synovial sarcoma with specific HLA types and MAGE-A4 expression.
StagingClick to collapse
American Joint Committee on Cancer (AJCC) Cancer Staging Manual, 8th Edition (2017) – TNM classification with histologic grade (FNCLCC). Separate staging systems exist for: (1) head and neck, (2) trunk and extremities, (3) abdomen and thoracic visceral organs, (4) retroperitoneum. Grade is determined by the FNCLCC system (tumor differentiation, mitotic count, necrosis) [ST-4 through ST-7].
T Categories
| Stage | Description |
|---|---|
| TX | Primary tumor cannot be assessed. |
| T0 | No evidence of primary tumor (for trunk/extremities and retroperitoneum). Not defined for head/neck. |
| T1 | Trunk/extremities, retroperitoneum: Tumor ≤5 cm in greatest dimension. Head/neck: Tumor ≤2 cm. |
| T2 | Trunk/extremities, retroperitoneum: Tumor >5 cm and ≤10 cm. Head/neck: Tumor >2 cm to ≤4 cm. |
| T3 | Trunk/extremities, retroperitoneum: Tumor >10 cm and ≤15 cm. Head/neck: Tumor >4 cm (no further size subdivision). |
| T4 | Trunk/extremities, retroperitoneum: Tumor >15 cm. Head/neck: Tumor with invasion of adjoining structures – T4a: orbital, skull base/dural, central compartment viscera, facial skeleton, pterygoid muscles; T4b: brain parenchyma, carotid artery encasement, prevertebral muscle invasion, CNS perineural spread. |
| T4a | Abdomen/thoracic visceral organs: Invades serosa or visceral peritoneum. |
| T4b | Abdomen/thoracic visceral organs: Extension beyond serosa (mesentery). |
| T4c | Abdomen/thoracic visceral organs: Multifocal (3-5 sites). |
N Categories
| Stage | Description |
|---|---|
| N0 | No regional lymph node metastasis or unknown lymph node status. |
| N1 | Regional lymph node metastasis (for all sites). |
M Categories
| Stage | Description |
|---|---|
| M0 | No distant metastasis. |
| M1 | Distant metastasis. |
Stage Groupings
| Group | Criteria | Clinical Meaning | Five Yr Survival | Treatment Intent |
|---|---|---|---|---|
| Stage IA | T1, N0, M0, G1 or GX (for trunk/extremities: T1 N0 M0 G1/GX; for head/neck: T1 N0 M0 G1/GX; for retroperitoneum: T1 N0 M0 G1/GX). For abdomen/thoracic visceral organs, no stage grouping is recommended. | Low-grade, small tumor with good prognosis. | Not explicitly stated in source; survival data not provided in the staging tables. | Curative – surgical resection alone or with selective RT. |
| Stage IB | T2, T3, or T4, N0, M0, G1/GX (trunk/extremities and retroperitoneum). For head/neck: T2-4 N0 M0 G1/GX. | Low-grade, larger tumor but still low grade, favorable biology. | Not explicitly stated. | Curative – surgery ± RT. |
| Stage II | Trunk/extremities and retroperitoneum: T1 N0 M0 G2 or G3. For head/neck: T1 N0 M0 G2 or G3. (Note: For abdomen/thoracic visceral organs, no stage grouping.) | High-grade, small tumor; moderate risk of metastasis. | Not explicitly stated. | Curative – surgery with RT (category 1) ± chemotherapy (category 2B). |
| Stage IIIA | Trunk/extremities and retroperitoneum: T2 N0 M0 G2/G3. | High-grade, moderate-sized tumor; increased risk of recurrence and metastasis. | Not explicitly stated. | Curative – multimodality therapy (surgery, RT, chemotherapy). |
| Stage IIIB | Trunk/extremities and retroperitoneum: T3 or T4 N0 M0 G2/G3. For head/neck: T2-4 N0 M0 G2/G3 (no further subdivision). | High-grade, large or locally invasive tumor; high risk of recurrence and metastasis. | Not explicitly stated. | Curative – multimodality therapy; neoadjuvant approaches preferred. |
| Stage IV | Any T, N1, M0, any grade (any site) OR any T, any N, M1, any grade. | Regional lymph node involvement or distant metastases. Prognosis is poor. | Not explicitly stated; median survival for metastatic disease is approximately 12-18 months based on clinical data cited in the discussion (MS-19). | Palliative – systemic therapy, local therapies for oligometastases, best supportive care. |
Staging Pearls
- AJCC 8th edition uses a single classification for T based on size (except head/neck where invasion defines T4). Grade (FNCLCC) is the dominant prognostic factor, dividing stage groups primarily by grade.
- For head and neck, there is no recommended stage grouping (data collection ongoing) [ST-4].
- For abdomen and thoracic visceral organs, no prognostic stage grouping is recommended [ST-6].
- The FNCLCC grade is calculated from scores for differentiation (1-3), mitotic count (1-3: 0-9/10 HPF = 1, 10-19 = 2, ≥20 = 3), and necrosis (0: no necrosis, 1: <50%, 2: ≥50%). Total score: G1 = 2-3, G2 = 4-5, G3 = 6-8 [ST-4].
- Lymph node involvement (N1) automatically assigns stage IV regardless of T or G.
- For retroperitoneal/intra-abdominal sarcomas, T4 is defined by multifocality (T4a: 2 sites, T4b: 3-5 sites, T4c: >5 sites) [ST-6].
- The guidelines reference AJCC 8th edition but note that new staging systems may be updated (e.g., AJCC 9th edition anticipated). Always verify current edition.
Management PrinciplesClick to collapse
The management of soft tissue sarcoma (STS) is founded on a multidisciplinary, multimodality treatment philosophy. Prior to the initiation of therapy, all patients should be evaluated and treated by a multidisciplinary team with expertise and experience in sarcoma management [EXTSARC-1]. This team should include specialists in surgical oncology, medical oncology, radiation oncology, pathology, radiology, and rehabilitation. The anatomic site of the primary tumor (extremity/body wall, head/neck, retroperitoneum/intra-abdominal) and histologic subtype are critical determinants of treatment strategy [MS-2]. The treatment philosophy emphasizes individualized care based on stage, grade, resectability, functional outcomes, and patient preferences. Limb-sparing surgery with negative margins is the primary goal for extremity tumors, with amputation reserved for cases where gross total resection would render the limb nonfunctional or patient preference [SARC-D 1 of 4]. For retroperitoneal/intra-abdominal sarcomas, complete surgical resection with oncologically appropriate margins is the primary curative approach, but given proximity to critical structures, close margins may be necessary [RETSARC-2]. Neoadjuvant and adjuvant radiation therapy and systemic therapy are integrated to improve local control and reduce recurrence risk, particularly for high-grade or large tumors. For desmoid tumors, initial observation is appropriate given the potential for spontaneous regression, while active therapy is reserved for progression causing morbidity [DESM-2, DESM-3]. The treatment philosophy for rhabdomyosarcoma (RMS) requires risk-stratified multimodality therapy, and referral to centers with pediatric oncology expertise is strongly recommended [RMS-1]. For borderline/malignant phyllodes tumors, surgical excision with ≥1 cm margins is the cornerstone, with adjuvant radiation considered for high-risk features [PHYLLSARC-1, PHYLLSARC-2]. The overall approach integrates evidence-based recommendations with the recognition that STS is rare and heterogeneous, requiring expert multidisciplinary input.
Curative (localized disease)
Stage I, II, III, and select Stage IV (any T, N1, M0) resectable with acceptable functional outcomes
Surgery to obtain oncologically appropriate margins is the primary treatment. For stage I (low grade), surgery alone is often sufficient; for stage II/III (high grade), surgery is combined with neoadjuvant or adjuvant radiation therapy (category 1 for preoperative RT) with or without systemic therapy. For select histologies (e.g., UPS-related sarcomas), neoadjuvant pembrolizumab with RT may be considered [EXTSARC-3, SARC-G 1 of 14]. For retroperitoneal sarcoma, neoadjuvant RT may be considered in selected high-risk cases [RETSARC-2]. For localized malignant phyllodes, surgical resection with ≥1 cm margins followed by consideration of adjuvant RT is the approach [PHYLLSARC-2].
Curative but with functional compromise (extremity/trunk/head/neck)
Stage II/III resectable but with unacceptable functional outcomes or unresectable primary disease
Neoadjuvant RT or systemic therapy is used to attempt downstaging to allow for function-preserving surgery. If response allows, resection is performed. If not, options include amputation, definitive RT, isolated limb perfusion/infusion (in experienced centers), or palliative treatments [EXTSARC-4].
Palliative (advanced/metastatic disease)
Stage IV (synchronous or recurrent) with disseminated metastases or oligometastatic disease not amenable to local therapy
Systemic therapy is the mainstay. For oligometastatic disease with limited tumor bulk, local therapies such as metastasectomy, SBRT, ablation, or embolization can be considered. For disseminated disease, palliative systemic therapy, RT, symptom-directed surgery, or best supportive care are options. Observation is appropriate for asymptomatic patients with indolent tumor biology [EXTSARC-5, EXTSARC-6, RETSARC-5].
Active surveillance / observation
Desmoid tumors in anatomic locations where progression would not be morbid, or stable/regressing tumors
Initial observation with imaging every 3 months is recommended. Spontaneous regression occurs in up to 20% of patients. Therapy (systemic therapy, surgery, ablation, RT) is initiated only for documented progression with potential morbidity or significant symptoms [DESM-2, DESM-3, DESM-4].
All patients should be evaluated and treated by a multidisciplinary team with expertise and experience in sarcoma management [EXTSARC-1]. The multidisciplinary surgical team should include expertise in the management of sarcomas at specific anatomic sites as well as reconstruction [SARC-D 1 of 4]. For retroperitoneal/intra-abdominal sarcomas, a multidisciplinary sarcoma panel should review the patient if possible [RETSARC-1]. For RMS, multidisciplinary evaluation involving pediatric, medical, surgical, and radiation oncologists is strongly encouraged, and referral to institutions with expertise in treating RMS is strongly recommended [RMS-1]. For desmoid tumors, all patients should be managed by a multidisciplinary team with expertise and experience in desmoid tumors [DESM-1]. For phyllodes tumors, a multidisciplinary team with expertise and experience in phyllodes tumor is required [PHYLLSARC-1, PHYLLSARC-2].
Performance status is considered in treatment decisions, particularly for advanced/metastatic disease where it influences the choice of systemic therapy, intensity of local therapies, and suitability for surgery. The guideline references performance status in selection of patients for metastasectomy, SBRT, and palliative RT [EXTSARC-5, EXTSARC-6, RETSARC-5]. Pazopanib is a first-line option for patients aged ≥60 years or those ineligible for IV systemic therapy [SARC-G 1 of 14]. For unresectable disease, observation is an option for asymptomatic patients with indolent tumor biology [EXTSARC-4, RETSARC-4]. The panel recommends preoperative assessment of medical comorbidities, physical endurance/frailty, and nutritional status prior to surgery [SARC-D 3 of 4].
Management PathwaysClick to collapse
Branching: Tumor stage (IA T1≤5 cm, IB T2-4), Grade (G1, GX), Resectability, Functional outcome
Branching: Stage (II, III, select IV [any T, N1, M0]), Grade (G2, G3), Resectability with acceptable function, Histology, Tumor size, Location
Branching: Resectability status, Functional outcome, Previous RT, Symptom burden
Branching: Extent of metastatic disease (oligometastatic vs. disseminated), Tumor bulk, Ability to control primary, Performance status
Branching: Type of recurrence (local vs. metastatic: single organ limited vs. disseminated vs isolated nodal), Prior treatment, Disease-free interval, Resectability, Performance status
Branching: Histology (GIST vs. desmoid vs. sarcoma), Grade, Resectability, Tumor size, Risk of local recurrence
Branching: Previous treatment, Biopsy confirmation, Symptom burden, Tumor biology (indolent vs. progressive)
Branching: Extent of metastases (oligometastatic vs. disseminated), Ability to control primary, Performance status
Branching: Anatomic location (critical vs. non-critical), Symptoms, Progression on imaging
Branching: Anatomic location (intra-abdominal/retroperitoneal vs. all other sites), Surgical margin status, Previous therapies, Patient preference
Branching: Histology (pleomorphic vs. non-pleomorphic), Age, Anatomic site
Branching: Histology (non-pleomorphic subtypes), Risk stratification (pediatric protocols), Age, Fusion status
Branching: Anatomic location (extremity/trunk vs. retroperitoneum/paratesticular), Evidence of dedifferentiation
Branching: Anatomic location (retroperitoneum/paratesticular), Presence of dedifferentiation
Branching: Tumor grade (borderline vs. malignant), Localized vs. advanced, Margin status
Branching: Resectability (localized resectable vs. unresectable vs. synchronous Stage IV), Margin status, Risk features
Pretreatment EvaluationClick to collapse
Essential (All Primary Sites)
Useful in Certain Circumstances (All Sites)
Special Considerations for Unique Histologies
SurgeryClick to collapse
Surgical resection with oncologically appropriate negative margins is the standard primary treatment for most patients with STS. The goal of surgery is functional limb preservation for extremity sarcomas when possible, and complete tumor removal for all sites. Surgery is often combined with RT and/or systemic therapy to improve local control and reduce recurrence risk. For selected low-grade tumors, surgery alone may be definitive. For desmoid tumors, surgery is less preferred and reserved for specific situations. For phyllodes tumors, surgery with ≥1 cm margins is the cornerstone of treatment.
The multidisciplinary surgical team should include expertise in the management of sarcomas at specific anatomic sites as well as reconstruction [SARC-D 1 of 4].
Pretreatment pathologic diagnosis (histologic subtype and grade) is almost always necessary for optimal treatment planning, including surgical margin planning and discussion of neoadjuvant therapy [SARC-D 1 of 4].
Percutaneous core needle biopsy is preferred; the biopsy tract should avoid potential tumor contamination of uninvolved compartments and be in line with future surgical resection incision. In certain situations, MRI and FDG-PET/CT imaging prior to biopsy may allow targeting of enhancing/metabolically active components [SARC-D 1 of 4].
There is no clarity in the literature on when sentinel node staging in STS should be done; multidisciplinary discussion should occur regarding its role in certain histologies (clear cell, angiosarcoma, epithelioid, alveolar RMS) [SARC-D 1 of 4].
Ideal surgical procedure resects tumor with pathologically negative resection margins. However, planned close margins or microscopically positive margins may be appropriate to preserve critical structures (major vessels, nerves, bones, joints), especially in multimodality therapy [SARC-D 1 of 4].
For extremity sarcomas, the goal should be functional limb preservation within the realm of appropriate oncologic resection ('limb-sparing surgery'). Radical excision/entire anatomic compartment resection is not routinely necessary [SARC-D 1 of 4].
Prior to considering amputation, patients should be evaluated by a surgeon with expertise in the treatment of soft tissue sarcomas. Amputation should be considered for patient preference or if gross total resection would render the limb nonfunctional [SARC-D 1 of 4].
For patients with previous unplanned excision: staging imaging of primary tumor site determines optimal management. For gross residual tumor, follow EXTSARC-1. For no gross residual tumor but nononcologic margins, manage as 'Failure to Obtain Oncologically Appropriate Margins' [SARC-D 1-2 of 4].
For retroperitoneal/intra-abdominal sarcomas, unplanned spillage of microscopic tumor into the free intra-abdominal cavity is associated with increased risk for future sarcomatosis [SARC-D 2 of 4].
Surgical technique: ideally, prior surgical or biopsy site contaminated with microscopic tumor should be excised en bloc with definitive resection if technically possible with acceptable morbidity. Dissection through grossly normal tissue planes. Major vessels/nerves do not need resection if adventitia/perineurium removed and underlying structures not involved with gross tumor [SARC-D 2 of 4].
For certain highly infiltrative histologies (myxofibrosarcoma, DFSP), staged resections with temporary wound coverage to obtain negative pathologic margins prior to definitive closure/reconstruction can reduce local recurrence risk [SARC-D 2 of 4].
Prehabilitation and rehabilitation: when significant postoperative dysfunction is anticipated (extremity amputation, major limb-sparing, truncal/intra-abdominal resections), strong consideration should be given to outpatient prehabilitation and rehabilitation to optimize functional outcomes and quality of life [SARC-D 3 of 4].
Prior to amputation or major limb-sparing surgery, formal PM&R consultation should be offered. Multimodality prehabilitation (exercise, nutritional supplementation, anxiety-coping) is associated with greater improvements in functional capacity and lower risk for postoperative complications following major abdominal surgery [SARC-D 3 of 4].
Rehabilitation plan should consider oncology treatment-related side effects (lymphedema, neuropathy, fatigue, radiation fibrosis, impaired bone healing). Pain management integrated early, especially for neuropathic pain or phantom limb pain. Psychological concerns addressed with referrals to mental health professionals and peer support groups [SARC-D 3-4 of 4].
Procedures
Limb-sparing surgery (wide local excision)
Primary management for most extremity and truncal STS. Preferred over amputation when oncologically appropriate margins can be achieved with acceptable functional outcome.
Amputation
Patient preference; or when gross total resection with limb-sparing surgery would render limb nonfunctional; or for recurrent disease not amenable to limb-sparing options. Amputation may improve local control in patients not candidates for limb-sparing surgery [SARC-D 1 of 4].
Wide resection for retroperitoneal/intra-abdominal sarcoma
Primary treatment for resectable retroperitoneal/intra-abdominal STS. Surgery often results in physical disability affecting major organ systems (cardiopulmonary, nutrition, performance status) [SARC-D 3 of 4].
Surgery for desmoid tumors
Not first-line except in certain situations. May be considered for progressive, morbid, or symptomatic desmoid tumors when other therapies have failed or are not appropriate. Surgery often results in physical disability.
Surgery for phyllodes tumors (borderline/malignant)
Primary treatment for localized borderline/malignant phyllodes tumors. Due to high local recurrence rates with narrow/positive margins, attempts at nipple/skin sparing approach close to tumor is discouraged [PHYLLSARC-2A footnote k].
Radiation TherapyClick to collapse
Radiation therapy is a critical component of multimodality treatment for STS, primarily to improve local control when combined with surgery. It can be administered as neoadjuvant (preoperative), adjuvant (postoperative), definitive (for unresectable disease), or palliative treatment. The panel has expressed a general preference for preoperative over postoperative radiotherapy for extremity/body wall/head and neck STS due to lower total dose, smaller field sizes, and potential for reduced late toxicities, despite higher acute wound healing complications [SARC-E 1 of 6]. For retroperitoneal/intra-abdominal STS, neoadjuvant RT can be considered in selected high-risk patients, but adjuvant RT is discouraged routinely [SARC-E 3 of 6]. SBRT is used for metastatic disease and select primary tumors. Palliative RT improves symptoms from unresectable or metastatic disease.
Principles
- Radiation should be delivered using the most appropriate technique to cover target volume while maintaining dose constraints to normal tissues. Techniques include IMRT (preferred), 3D conformal RT, electron beam therapy, or proton beam therapy in challenging anatomic locations. Daily image guidance is essential to ensure adequate targeting and sparing of adjacent normal tissue [SARC-E 1 of 6].
- For extremity/body wall/head and neck: Total RT doses are always determined based on tissue tolerance. Neoadjuvant: 50-50.4 Gy (1.8-2 Gy/fraction). Adjuvant: 50-50.4 Gy to large volume followed by boost (10-16 Gy for negative margins, 16-18 Gy for R1, 20-26 Gy for R2). Brachytherapy can be used alone or with EBRT [SARC-E 1-2 of 6].
- For myxoid liposarcoma, a dose reduction to 36 Gy can be considered for preoperative RT [SARC-E 1 of 6].
- Conventionally fractionated RT remains standard. Moderately hypofractionated preoperative regimens have demonstrated acceptable early local control but long-term data not yet available; may be appropriate for select patients unable to receive standard course [SARC-E 1 of 6].
- For retroperitoneal/intra-abdominal: When EBRT used, IMRT/IGRT/proton beam therapy should be used to improve therapeutic ratio. Neoadjuvant doses: 50-50.4 Gy (1.8-2 Gy/fraction). Consider IORT boost for known/suspected positive margins (10-12.5 Gy for microscopic, 15 Gy for gross) [SARC-E 3 of 6].
- Alternative approach for retroperitoneal: 45-50 Gy in 25-28 fractions to entire CTV with dose-painted SIB to total 57.5 Gy in 25 fractions to high-risk retroperitoneal margin jointly defined by surgeon and radiation oncologist (no boost after surgery) [SARC-E 3 of 6].
- Adjuvant RT following surgery is discouraged for retroperitoneal/intra-abdominal sarcoma. If RT not given prior to surgery, consider follow-up with possible neoadjuvant RT at time of localized recurrence [SARC-E 3 of 6].
- For desmoid tumors: Definitive RT is an appropriate option primarily for non-mesenteric desmoid tumors, often reserved for patients who cannot tolerate or progress through systemic therapy and where surgery would be too morbid or result in positive margins. Recommended dose: 56 Gy in 28 fractions. Treat similarly to high-grade STS given infiltrative nature [SARC-E 2 of 6].
- For borderline/malignant phyllodes: General sarcoma dose guidelines utilized: 50-60 Gy in 1.8-2 Gy/fraction postoperatively. No data supporting hypofractionation. Timing of pre- vs postoperative RT determined in tandem with surgeon and multidisciplinary team based on tumor size, proximity to skin/chest wall, planned surgery extent, and reconstructive considerations [SARC-E 3 of 6].
- SBRT: Delivers ablative doses to tumors using specialized immobilization, treatment planning, and image guidance. Commonly used for metastatic sarcomas involving lungs, liver, bone, lymph nodes, and select primary tumors. Dose/fractionation determined by experienced radiation oncologist based on normal tissue constraints. Patient selection: oligometastatic disease, oligoprogressive disease with other sites stable, or treatment within previously irradiated field [SARC-E 4 of 6].
- Palliative RT: Dose/fractionation based on normal tissue constraints, performance status, patient prognosis, and prior treatment history. Patients with limited volume metastatic disease and excellent performance status may benefit from dose escalation through IMRT or SBRT. Prior irradiation to treatment site may benefit from IMRT or SBRT for safety of reirradiation [SARC-E 4 of 6].
Dose Frameworks
| Name | Total Dose | Dose Per Fraction | Fractions | Schedule | Indication |
|---|---|---|---|---|---|
| Neoadjuvant RT (extremity/body wall/head/neck) | 50-50.4 Gy | 1.8-2 Gy | 25-28 | Once daily, preoperative | Preferred approach for stage II-III STS. For myxoid liposarcoma, 36 Gy may be considered [SARC-E 1 of 6]. |
| Adjuvant RT (extremity/body wall/head/neck) – initial volume | 50-50.4 Gy | 1.8-2 Gy | 25-28 | Once daily, postoperative after wound healing | For patients who did not receive preoperative RT. Final dose determined by margin status: 60 Gy for R0, 66 Gy for R1 after boost [SARC-E 2 of 6]. |
| Adjuvant RT boost (extremity/body wall/head/neck) – R0 margins | 10-16 Gy boost | 1.8-2 Gy | 5-9 | After initial 50-50.4 Gy | For negative margins (final 60-66 Gy depending on margin). Boost may not be necessary for widely negative margins [SARC-E 2 of 6]. |
| Adjuvant RT boost – R1 margins | 16-18 Gy boost | 1.8-2 Gy | 8-10 | After initial 50-50.4 Gy | For microscopically positive margins (final dose 66-68 Gy) [SARC-E 2 of 6]. |
| Adjuvant RT boost – R2 margins | 20-26 Gy boost | 1.8-2 Gy | 10-14 | After initial 50-50.4 Gy | For gross residual disease (final dose 70-76 Gy) [SARC-E 2 of 6]. |
| Definitive RT for unresectable disease | ≥63 Gy; up to 70-80 Gy | 1.8-2 Gy (conventional) or hypofractionated alternatives | Variable | Once daily, or alternative hypofractionated regimens | For nonsurgical candidates with unresectable primary or metastatic disease [SARC-E 2 of 6]. |
| Neoadjuvant RT (retroperitoneal/intra-abdominal) | 50-50.4 Gy | 1.8-2 Gy | 25-28 | Once daily, preoperative. Consider IORT boost intraoperatively. | Selected patients at high risk for local recurrence [SARC-E 3 of 6]. |
| Alternative neoadjuvant RT (retroperitoneal) – dose-painted SIB | 45-50 Gy to CTV; 57.5 Gy SIB to high-risk margin | 1.8-2 Gy (CTV); 2.3 Gy (SIB) | 25 | Once daily, preoperative. No boost after surgery. To be used in experienced centers only [SARC-E 3 of 6]. | Alternative approach for retroperitoneal sarcoma. High-risk margins jointly defined by surgeon and radiation oncologist [SARC-E 3 of 6]. |
| Definitive RT for desmoid tumors | 56 Gy | 2 Gy | 28 | Once daily | For non-mesenteric desmoid tumors where surgery would be too morbid or would result in positive margins [SARC-E 2 of 6]. |
| Postoperative RT for phyllodes tumors | 50-60 Gy | 1.8-2 Gy | 25-33 | Once daily, postoperative | For malignant phyllodes tumors after breast conservation surgery (adjuvant RT recommended regardless of margin status); for high-risk features after mastectomy. Conventionally fractionated whole breast/post-mastectomy radiation recommended [SARC-E 3 of 6, PHYLLSARC-2A footnote i]. |
Approaches
| Name | Dose Fractionation | Concurrent Chemotherapy | Indication | Key Trial | Toxicities |
|---|---|---|---|---|---|
| Preoperative (Neoadjuvant) RT – Extremity/Body Wall/Head/Neck | 50-50.4 Gy in 25-28 fractions (1.8-2 Gy/fraction). Dose reduction to 36 Gy for myxoid liposarcoma. Hypofractionated regimens (e.g., 5 fractions) may be considered for select patients [SARC-E 1 of 6]. | Not typically used with RT alone. However, for select histologies (UPS-related sarcomas), neoadjuvant pembrolizumab with RT followed by adjuvant pembrolizumab is an option [SARC-G 1 of 14]. | Category 1 recommendation for stage II-III STS. Preferred over postoperative RT due to lower total dose, smaller fields, and reduced late toxicities. Particularly useful when negative margins are anticipated and for large tumors [SARC-E 1 of 6]. | Canadian Sarcoma Group randomized trial demonstrated similar local control and PFS but greater acute wound complications (35% vs 17%) for preop vs postop RT [SARC-E 1 of 6]. RTOG 0630 showed reduced late toxicity with image-guided RT [SARC-E 1 of 6]. | Acute wound healing complications (especially lower extremity), fatigue, skin reaction, edema. Late: fibrosis, joint stiffness, edema, lymphedema, bone necrosis, secondary malignancy. |
| Postoperative (Adjuvant) RT – Extremity/Body Wall/Head/Neck | Initial 50-50.4 Gy in 25-28 fractions to large volume, followed by boost to tumor bed (10-16 Gy for R0, 16-18 Gy for R1, 20-26 Gy for R2). Total dose 60-70 Gy. Alternative: brachytherapy alone (45 Gy LDR or 36 Gy HDR for negative margins) or with EBRT boost [SARC-E 2 of 6]. | Not routinely used. | For patients who did not receive preoperative RT, especially when margins are close or positive. Category 1 recommendation. Potential benefits: ability to review final pathology and margin status, lower wound complication rates [SARC-E 2 of 6]. | Randomized study by Yang et al showed significant reduction in 10-year local recurrence with postoperative RT in high-grade lesions (0% vs 22%) and low-grade (5% vs 32%) [MS-14]. | Higher late toxicity compared to preoperative: fibrosis, edema, joint stiffness due to larger fields and higher doses. Intervals beyond 8 weeks between resection and RT are not recommended [MS-8]. |
| Definitive RT for Unresectable Disease | At least 63 Gy, up to 70-80 Gy based on normal tissue tolerance. Alternative hypofractionated regimens may be considered [SARC-E 2 of 6]. | Not routinely used. | Nonsurgical candidates with unresectable primary or metastatic disease. Long-term local control may be inferior to multimodality therapy [SARC-E 2 of 6]. | Single-institution study showed local control 51% for tumors <5 cm vs 9% for >10 cm; better outcomes with ≥63 Gy [MS-19]. | Fatigue, skin reaction, fibrosis, edema, potential damage to adjacent organs depending on location. |
| Neoadjuvant RT for Retroperitoneal/Intra-Abdominal Sarcoma | 50-50.4 Gy in 25-28 fractions (1.8-2 Gy/fraction). Consider IORT boost: 10-12.5 Gy for microscopic positive margin, 15 Gy for gross disease. Alternative: 45-50 Gy in 25-28 fractions with dose-painted SIB to 57.5 Gy in 25 fractions (experienced centers only) [SARC-E 3 of 6]. | Not routinely used. | Selected patients at high risk for local recurrence. IMRT/IGRT/proton therapy recommended to improve therapeutic ratio [SARC-E 3 of 6]. | EORTC-62092 (STRASS) phase III trial: neoadjuvant RT + surgery vs surgery alone for primary retroperitoneal sarcoma. Primary endpoint not met (median abdominal RFS 4.5 vs 5 years, HR 1.01). Post-hoc analysis suggested benefit for liposarcoma [MS-23]. | Lymphopenia (77%), anemia (12%), hypoalbuminemia (12%) in STRASS trial. Potential bowel toxicity. Adjuvant RT discouraged [SARC-E 3 of 6]. |
| SBRT for Metastases / Select Primary Tumors | Variable; determined by experienced radiation oncologist based on normal tissue constraints. Commonly used for lung, liver, bone, lymph node metastases. Dose/fractionation: e.g., 30-60 Gy in 3-5 fractions for lung metastases [SARC-E 4 of 6]. | May be used sequentially with systemic therapy. | Patients with oligometastatic disease, oligoprogressive disease with other sites stable/controlled, or treatment within previously irradiated field [SARC-E 4 of 6]. | Retrospective studies: high rates of local control with favorable toxicity for sarcoma pulmonary metastases (Dhakal et al, Int J Radiat Oncol Biol Phys 2012) [SARC-E 6 of 6]. | Fatigue, pneumonitis (lung), hepatitis (liver), bone pain flare, rib fracture, radiation necrosis (brain). Low rates of grade 3+ toxicity in reported series. |
| Palliative RT | Determined based on normal tissue constraints, performance status, prognosis, prior treatment history. Hypofractionated regimens common (e.g., 30 Gy in 10 fractions, 20 Gy in 5 fractions, 8 Gy single fraction for bone metastases). Patients with limited volume and excellent performance status may benefit from dose escalation with IMRT or SBRT [SARC-E 4 of 6]. | Not typically used. | Symptomatic unresectable or metastatic disease: pain, bleeding, obstruction, neurologic compromise. | Owen D, et al. Pract Radiat Oncol 2025;15:e388-e395 [EXTSARC-6 footnote ee]. | Acute: fatigue, skin reaction, nausea, diarrhea (depending on site). Late: fibrosis, fistula, necrosis, secondary malignancy. |
Systemic TherapyClick to collapse
Systemic therapy for soft tissue sarcoma is tailored by histologic subtype, stage, and treatment setting (neoadjuvant/adjuvant, first-line advanced/metastatic, subsequent lines). Anthracycline-based regimens are the backbone for most subtypes. The NCCN guideline provides extensive histology-specific recommendations [SARC-G 1-7 of 14]. Neoadjuvant/adjuvant therapy is considered for high-risk patients to improve local control and reduce distant recurrence. For advanced/metastatic disease, first-line options include doxorubicin, epirubicin, liposomal doxorubicin, and combination regimens (AIM, AD, epirubicin/ifosfamide). Targeted agents (pazopanib, eribulin, trabectedin, TKIs) and immunotherapies (pembrolizumab, nivolumab ± ipilimumab) are used in subsequent lines or for specific molecular subtypes (NTRK fusions, TMB-H, MSI-H). Dexrazoxane may be added as cardioprotectant for high-dose anthracyclines (doxorubicin >250 mg/m2) [SARC-G 1 of 14 footnote d]. The panel emphasizes that patients should be managed by a multidisciplinary team with sarcoma expertise prior to initiating therapy.
Key Regimens
Treatment Response AssessmentClick to collapse
Title
Principles of Treatment Response Assessment and Follow-Up
Timing
Assessment of treatment response is tailored to disease stage, histology, and treatment modality. For neoadjuvant therapy, response evaluation is performed during and after preoperative chemotherapy or radiation using imaging, with FDG-PET/CT optional to determine histopathologic response. For advanced/metastatic disease, response is assessed every 2-3 cycles of systemic therapy (typically every 6-12 weeks) using RECIST criteria or FDG-PET/CT. For unresectable disease treated with definitive RT or systemic therapy, follow-up imaging is recommended to assess treatment response. For patients undergoing preoperative RT, a 3- to 6-week interval is necessary before resection to allow acute reactions to subside [MS-7]. After completion of primary treatment (surgery ± RT ± systemic therapy), surveillance follows a risk-stratified schedule based on stage and histology.
Response Logic
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FDG-PET imaging (CT or MRI) may be useful in determining response to neoadjuvant systemic therapy. A reduction in SUVmax of ≥40% after preoperative chemotherapy is associated with significantly lower risk of recurrence and death after complete resection and postoperative RT [EXTSARC-3 footnote w, MS-12-13].
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A 35% reduction in SUV after the first cycle of chemotherapy was a sensitive predictor of histopathologic response in a prospective study of 50 patients with resectable high-grade STS [MS-12-13].
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For retroperitoneal/intra-abdominal STS: patients whose tumors become resectable following primary treatment (systemic therapy and/or RT) should be managed as described for resectable disease [RETSARC-4].
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For desmoid tumors: response to therapy is assessed with imaging. Spontaneous regression has been reported in up to 20% of patients. Response to RT is slow, with continuing regression seen even after 3 years [MS-33].
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For phyllodes tumors: rapid growth pattern requires expedited evaluation. After neoadjuvant RT, surgical re-evaluation should occur during and immediately after preoperative RT to reassess resectability [PHYLLSARC-2A footnote f].
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For patients with metastatic disease, follow-up imaging including chest and other known sites of disease should be performed every 2-6 months for 2-3 years, then every 6 months to complete a total of 5 years, then annually [EXTSARC-5, SARC-A 3-4 of 5].
Imaging Recommendations
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Contrasted cross-sectional imaging with MRI (with and without contrast) is preferred over CT for primary site evaluation. CT is preferred for retroperitoneum. For long-term survivors, chest x-rays and nonionizing imaging modalities may be considered to minimize radiation exposure [SARC-A 1 of 5].
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Chest imaging: CT chest without contrast is preferred for detection of pulmonary metastases. For some histologies (e.g., WDLPS), routine chest imaging is not necessary [ALT/WDLPS-1 footnote d, SARC-A 2 of 5].
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Surveillance schedule by stage: Stage I: H&P every 3-6 months for 3 years, then annually. Consider chest imaging every 6-12 months. Periodic imaging of primary site based on risk of locoregional recurrence. Stage II/III and synchronous Stage IV: H&P and imaging of chest and other known sites of metastatic disease every 2-6 months for 2-3 years, then every 6 months to complete 5 years, then annually. Postoperative baseline imaging of primary site recommended [SARC-A 3-4 of 5].
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Retroperitoneal/intra-abdominal STS: follow-up imaging (chest/abdomen/pelvis CT preferred or MRI) every 3-6 months for 3 years, then every 6 months to complete 5 years, then annually. For well-differentiated liposarcoma, routine chest imaging is not necessary [SARC-A 4 of 5, RETSARC-3 footnote r].
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Desmoid tumors: imaging every 3-6 months for 3 years, then every 6-12 months thereafter. MRI is preferred. Ultrasound may be considered for select locations (e.g., abdominal wall) for long-term follow-up, done by an ultrasonographer experienced in musculoskeletal disease [SARC-A 5 of 5].
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Phyllodes tumors (malignant): H&P and imaging (CT C/A/P and breast/chest MRI with and without contrast) every 3-6 months for 3 years, then every 6 months to complete 5 years, then annually. Consider symptom-driven brain MRI for 5 years [PHYLLSARC-3].
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After 10 years, the likelihood of developing a recurrence is small and follow-up should be individualized [EXTSARC-3A footnote o].
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In situations where the area is easily followed by physical examination, imaging may not be required [EXTSARC-3A footnote n].
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Ultrasound may be used to detect early local recurrence and small nodules <0.5 cm; MRI should be used if ultrasound results are inconclusive [MS-20-21].
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Specific histologies require additional sites: ASPS (CNS MRI, bone scan); angiosarcoma (CNS MRI, regional lymph node basin imaging); myxoid/round cell liposarcoma (total spine MRI, WB MRI for soft tissues); leiomyosarcoma (abdomen/pelvis, bone scan); epithelioid sarcoma (abdomen/pelvis, regional nodes) [SARC-A 1-2 of 5].
Biopsy Or Salvage Logic
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If local recurrence is suspected during follow-up, biopsy should be performed to confirm diagnosis. For patients with previous unplanned excision, staging imaging determines optimal management [SARC-D 1 of 4].
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For patients with a local recurrence, treatment decisions should be made using the same algorithm as for a new primary lesion. If LR can be excised, decision regarding re-irradiation should be made on a case-by-case basis [EXTSARC-6 footnote ff].
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For recurrent disease (metastatic): If oligometastatic, local therapies (metastasectomy, SBRT, ablation, embolization) can be considered. For disseminated disease, systemic therapy, palliative RT, or observation (if asymptomatic) are options [EXTSARC-6, RETSARC-6].
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For retroperitoneal/intra-abdominal recurrence: biopsy should be considered if diagnosis is not clinically definitive. Surgery to obtain oncologically appropriate margins is recommended if resectable. Consider neoadjuvant therapy (RT if not previously given, systemic therapy) for selected cases [RETSARC-6].
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For desmoid tumors: disease progression on imaging (with or without symptoms) may trigger active therapy. Continuation of observation is appropriate for minimal symptoms and non-critical location [DESM-2, DESM-3].
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For malignant phyllodes: local recurrence is managed per initial treatment pathways. Oligometastatic disease: consider systemic therapy for all patients, metastasectomy (shown to improve OS in retrospective study: HR 0.33; 95% CI 0.14-0.78), RT/SBRT, ablation, embolization [PHYLLSARC-5, PHYLLSARC-5A footnote q].
SurveillanceClick to collapse
Clinical Follow Up Schedule
| Disease State | Schedule | Notes |
|---|---|---|
| Extremity/body wall/head/neck Stage I | H&P every 3–6 mo for 3 y, then annually | In areas easily followed by PE, imaging may not be required. |
| Extremity/body wall/head/neck Stage II/III and select IV | H&P and imaging every 3–6 mo for 3 y, then every 6 mo to complete 5 y, then annually | More intensive for first 3-5 years due to higher risk of dissemination. |
| Retroperitoneal/intra-abdominal STS (all stages) | Physical exam with imaging every 3–6 mo for 3 y, then every 6 mo to complete 5 y, then annually | For resected disease (RETSARC-3); for unresectable/stage IV, individualize. |
| Desmoid tumors | Imaging every 3–6 mo for 3 y, then every 6–12 mo thereafter | Initial imaging every 3 mo recommended; more frequent if symptomatic. |
| ALT/WDLPS (extremity/trunk/abdominal wall) | H&P every 6–12 mo for 2 y, then annually | Imaging of primary site based on risk; routine chest imaging not needed. |
| Borderline/Malignant Phyllodes tumor (localized/oligometastatic) | H&P and imaging (CT C/A/P and breast/chest MRI with/without contrast) every 3–6 mo for 3 y, then every 6 mo to 5 y, then annually | Consider symptom-driven brain MRI for 5 y for malignant phyllodes. |
Imaging Strategy
| Modality | Preferred | Alternative | Notes |
|---|---|---|---|
| Primary site | MRI with and without contrast (for extremity/body wall/head/neck/cardiac) | CT with contrast (for retroperitoneum) | US may be used for early detection of local recurrence (<0.5 cm nodules) or to differentiate solid nodule vs seroma/hematoma, but should be performed by experienced ultrasonographer. For long-term survivors, nonionizing modalities preferred. |
| Lungs (for all STS except WDLPS) | CT chest without contrast | Chest radiograph (less sensitive) | |
| CNS (brain) | MRI brain with and without contrast | CT brain | |
| Abdomen/pelvis | |||
| Spine (total spine MRI) | Due to higher risk of spine metastases. | ||
| Soft tissues (whole body MRI preferred) | PET/CT may not identify extrapulmonary disease. | ||
| FDG-PET (CT or MRI) | FDG-PET/MRI acceptable if available. Consider for restaging after neoadjuvant therapy (change in ≥40% SUVmax associated with improved recurrence-free survival [Schuetze 2005]). | ||
| Regional lymph node basin | CT or FDG-PET imaging (CT or MRI) |
Laboratory Monitoring
No specific laboratory monitoring is outlined in the guideline beyond routine clinical care for chemotherapy toxicity and disease assessment. For patients on systemic therapy, complete blood counts, renal and hepatic function, and cardiac function (ECHO for anthracyclines) should be monitored as per standard of care and package inserts of individual agents.
Supportive Follow Up
- Assessment for rehabilitation needs: all patients who have undergone limb-sparing or amputative surgery should be offered PM&R consultation, prehabilitation (if time permits), and ongoing rehabilitation [SARC-D 3 of 4].
- Distress screening: use NCCN Distress Thermometer at follow-up visits [EXTSARC-1].
- Genetic counseling referral: for patients with Li-Fraumeni syndrome, neurofibromatosis, Lynch syndrome, FAP/Gardner syndrome, hereditary retinoblastoma, Carney-Stratakis syndrome, or personal/family history suggestive of other cancer predisposition syndromes [SARC-H, EXTSARC-1].
- Long-term survivor care: after 5–10 years, follow-up should be individualized; chest x-rays and nonionizing imaging may be used to minimize radiation exposure [SARC-A].
- Psychosocial support and peer support groups should be offered.
ComplicationsClick to collapse
Disease-Related
| Complication | Management |
|---|---|
| Local recurrence | Re-resection if feasible; consider RT (if not previously given) or re-irradiation with brachytherapy/IMRT/proton therapy; systemic therapy for high-risk or unresectable recurrences. |
| Distant metastasis (most commonly lung; also liver, bone, peritoneum, soft tissues, spine depending on histology) | Metastasectomy for oligometastatic disease (e.g., pulmonary resection); SBRT for selected lung/liver/bone metastases; ablation/embolization for liver metastases; systemic therapy for disseminated disease. |
| Lymph node metastasis (e.g., in angiosarcoma, clear cell sarcoma, epithelioid sarcoma, alveolar rhabdomyosarcoma) | Regional lymph node dissection; consider RT ± systemic therapy. |
| Functional morbidity from primary tumor (e.g., limb dysfunction, pain, bleeding, infection) | Multimodality management including surgery, RT, systemic therapy; prehabilitation and rehabilitation; palliative interventions for fungating/necrotic tumors. |
Supportive CareClick to collapse
The NCCN Soft Tissue Sarcoma guidelines emphasize that all patients should be treated by a multidisciplinary team with expertise in sarcoma. Supportive care is integrated throughout the management pathway, including prehabilitation, rehabilitation, distress assessment, and management of treatment side effects. While the guideline does not provide exhaustive supportive care protocols, key elements are outlined in the Principles of Surgery (SARC-D) and by references to NCCN palliative care and distress management guidelines. Dexrazoxane is recommended as a cardioprotectant for patients receiving high cumulative doses of doxorubicin (>250 mg/m²) [SARC-G 8 of 14]. The use of growth factors (G-CSF) is implied in dose-dense regimens (e.g., IFADIC given every 14 days with growth factor support) [Fakhrai 2010]. Pain management should be integrated early into the rehabilitation plan, especially for neuropathic pain and phantom limb sensation [SARC-D 4 of 4]. Psychosocial support, including peer support groups, is recommended for all patients.
Prehabilitation for retroperitoneal/intra-abdominal sarcoma should include nutritional supplementation as part of multimodality prehabilitation (exercise, nutrition, anxiety-coping) to improve functional capacity and reduce postoperative complications [SARC-D 3 of 4]. Specific nutritional guidelines are not provided but are considered part of standard oncology supportive care.
The guideline does not specify antiemetic protocols; however, since anthracycline and ifosfamide-based regimens are highly emetogenic, standard NCCN antiemesis guidelines should be applied. The use of mesna for ifosfamide is recommended to prevent hemorrhagic cystitis [SARC-G 8 of 14].
Growth factor support (filgrastim, lenograstim) is used in dose-intensive regimens such as the IFADIC regimen every 14 days [Fakhrai 2010] and in the MAID chemoradiation protocol [Kraybill 2006]. No specific guidance on primary prophylaxis is given, but it is implied for regimens with high febrile neutropenia risk.
No specific VTE prophylaxis recommendations are provided in the STS guideline. Standard oncology VTE risk assessment and prophylaxis per NCCN guidelines should be applied, particularly for patients undergoing major surgery or receiving chemotherapy.
Pain management should be integrated into the rehabilitation plan early, especially for neuropathic pain or phantom limb sensation after amputation. Interventions can include mirror therapy, motor imagery, massage, oral and topical analgesics, coping strategies, and patient education [SARC-D 4 of 4]. For painful musculoskeletal metastases, ablation (including cement augmentation) can be used for pain palliation [SARC-F 2 of 3].
All patients should be assessed for distress using the NCCN Distress Thermometer and Problem List, which includes social determinants of health [EXTSARC-1]. Peer support groups should be offered. Referral to appropriate mental health professionals is recommended for body image issues and distress related to surgery/decreased physical ability [SARC-D 4 of 4].
No specific dental care recommendations are provided in the guideline. Since some chemotherapy agents (e.g., ifosfamide, doxorubicin) can cause mucositis and immunosuppression, standard oral care protocols are advisable.
PrognosisClick to collapse
Soft tissue sarcomas (STS) are rare, accounting for approximately 1% of adult malignancies. In 2022, an estimated 13,190 new cases and 5,130 deaths were projected in the US [Siegel 2022]. Prognosis depends critically on histologic grade, tumor size, depth, site, margin status, and subtype. High-grade tumors have significantly worse outcomes; the FNCLCC grading system (based on differentiation, mitotic count, and necrosis) is the standard three-tier system used for risk stratification [ST-5]. Retroperitoneal sarcomas generally have poorer prognosis than extremity sarcomas due to late presentation and difficulty achieving negative margins. Desmoid tumors (aggressive fibromatosis) are non-metastasizing but can cause significant local morbidity; spontaneous regression occurs in up to 20% of patients [DESM-2]. Rhabdomyosarcoma (RMS) in adults has a worse prognosis than in children: 5-year overall survival (OS) rates of 27% in adults versus 63% in children [Sultan 2009]. For pleomorphic RMS, 5-year OS in adults is approximately 40% [Ferrari 2003]. Advanced/metastatic STS has a poor disease-free interval; median survival is on the order of 12–18 months. For localized STS treated with curative intent, reported 5-year OS varies widely: for high-risk extremity STS, the SMAC meta-analysis reported 5-year OS of 64–65% [SMAC 1997]; the Italian cooperative trial showed 66% vs 46% (p=0.04) with adjuvant chemotherapy [Frustaci 2001]; and the MAID chemoradiation series reported 87% vs 58% (p=0.0003) compared with historical controls [DeLaney 2003]. In the RTOG 9514 trial of neoadjuvant chemoradiation, 5-year OS was 71% [Kraybill 2010]. For retroperitoneal STS, the STRASS trial reported no significant difference in abdominal recurrence-free survival between neoadjuvant RT plus surgery vs surgery alone (HR 1.01, p=0.95) [Bonvalot 2020], underscoring the need for individualized risk assessment.
Prognostic Factors
- Histologic grade (FNCLCC or NCI system)
- Surgical margin status (negative vs positive)
- Tumor size (T-stage)
- Tumor depth (superficial vs deep)
- Anatomic site (extremity vs retroperitoneal vs head/neck)
- Histologic subtype (e.g., alveolar soft part sarcoma, synovial sarcoma, dedifferentiated liposarcoma, angiosarcoma)
- Presence of distant metastasis at diagnosis (stage IV)
- Response to neoadjuvant therapy (e.g., pathologic response, FDG-PET SUV change)
- Lymph node involvement (N1 disease)
- Patient age and performance status
- Genetic alterations (e.g., PAX3-FOXO1 vs PAX7-FOXO1 in alveolar RMS, CTNNB1 mutation in desmoids)
- Molecular subtype (e.g., SS18-SSX fusion type in synovial sarcoma)
Follow UpClick to collapse
Post Curative Treatment
Post-treatment follow-up is risk-stratified by disease stage and site. For extremity/body wall/head/neck STS, the schedule is as follows: Stage I – H&P every 3–6 months for 3 years, then annually. Baseline and periodic imaging of the primary site based on risk of locoregional recurrence. Chest imaging (CT without contrast preferred or CXR) every 6–12 months [EXTSARC-2, SARC-A]. For Stage II/III and select Stage IV (any T, N1, M0) – H&P and imaging every 3–6 months for 3 years, then every 6 months to complete 5 years, then annually. Chest imaging and imaging of other known metastatic sites should be performed every 2–6 months for 2–3 years, then every 6 months to 5 years, then annually. Postoperative baseline and periodic imaging of the primary site are recommended [SARC-A 4 of 5]. For retroperitoneal/intra-abdominal STS – physical exam with imaging (CT chest/abdomen/pelvis preferred or MRI) every 3–6 months for 3 years, then every 6 months to complete 5 years, then annually [RETSARC-3, SARC-A 4 of 5]. For desmoid tumors – imaging every 3–6 months for 3 years, then every 6–12 months thereafter (MRI preferred; US may be considered for select locations) [SARC-A 5 of 5]. For ALT/WDLPS of extremity/abdominal wall/trunk – H&P every 6–12 months for 2 years, then annually. Imaging of primary site based on location and risk. Routine chest imaging is not necessary [ALT/WDLPS-1]. For borderline/malignant phyllodes – H&P and imaging (CT C/A/P and breast/chest MRI with contrast) every 3–6 months for 3 years, then every 6 months to 5 years, then annually. Symptom-driven brain MRI considered for 5 years for malignant phyllodes [PHYLLSARC-3, PHYLLSARC-4A].
Surveillance Rationale
The primary goal of surveillance is early detection of potentially curable recurrences, given that isolated local recurrences and oligometastatic (especially pulmonary) disease can be treated with salvage surgery or SBRT. Higher-grade/larger tumors have a higher risk of dissemination; internal hemorrhage/capsular rupture may also increase risk. Rigorous surveillance is most important in the first 3–5 years post-resection, as the majority of recurrences occur during this period. After 10 years, the likelihood of recurrence is small and follow-up should be individualized [EXTSARC-3A, SARC-A]. For desmoid tumors, surveillance focuses on local disease, as they do not metastasize. For WDLPS, chest imaging is not routinely needed due to low metastatic potential.
Late Effects Screening
- Late radiation toxicity: fibrosis, edema, joint stiffness, lymphedema, lymphangitis, secondary malignancy (sarcomas, skin cancers).
- Cardiotoxicity from anthracyclines: long-term cardiac monitoring (echocardiogram) recommended for patients who received cumulative doxorubicin >250 mg/m².
- Ifosfamide-related: nephrotoxicity (Fanconi syndrome), hemorrhagic cystitis, gonadal toxicity.
- Neuropathy (from chemotherapy: vinca alkaloids, taxanes, platinum agents).
- Functional disability after limb-sparing or amputation surgery: need for ongoing rehabilitation, prosthetics, and physical medicine and rehabilitation follow-up.
- Psychological late effects: body image issues, anxiety, depression; offer psychosocial support and peer groups.
- For patients who received radiation to the chest/abdomen: increased risk of cardiovascular disease, pulmonary fibrosis, secondary malignancies; consider age-appropriate cancer screening.
- For patients with Li-Fraumeni or other genetic syndromes: tailored surveillance for multiple primary cancers.
Recurrence Patterns
STS most commonly metastasizes to the lungs; retroperitoneal/intra-abdominal sarcomas more frequently metastasize to liver and peritoneum. Some histologies have unique patterns: myxoid/round cell liposarcoma to spine and soft tissues; alveolar soft part sarcoma to brain; angiosarcoma to lymph nodes and CNS; leiomyosarcoma to abdomen/pelvis and bone; rhabdomyosarcoma to lymph nodes and bone. Local recurrence rates for extremity STS with negative margins and appropriate RT are approximately 10-15% at 10 years. For retroperitoneal STS, local recurrence remains a significant problem even after macroscopically complete resection. Desmoid tumors have high local recurrence rates (up to 30-50% after surgery alone) but have negligible metastatic potential. Recurrence patterns guide surveillance imaging: chest CT, primary site MRI, and site-specific imaging based on histology [SARC-A; EXTSARC-6; RETSARC-3].
Key TrialsClick to collapse
| Acronym | Full Name | Year | N | Intervention | Comparator | Population | Primary Endpoint | Key Result | Secondary Outcomes | Practice Change | Journal |
|---|---|---|---|---|---|---|---|---|---|---|---|
| SMAC | Sarcoma Meta-Analysis Collaboration | 1997 | 1568 | Adjuvant doxorubicin-based chemotherapy | Observation with or without RT | Localized resectable soft-tissue sarcoma, meta-analysis of 14 randomized trials | Overall survival | Doxorubicin-based chemotherapy prolonged local and distant recurrence and overall relapse-free survival (HR not reported). OS benefit not significant but trend in favor of chemotherapy (absolute OS benefit ~4% at 5 years not statistically significant). | None reported beyond recurrence and OS | Established that adjuvant chemotherapy can reduce recurrence but survival benefit remains uncertain. | Lancet |
| EORTC 62931 | European Organisation for Research and Treatment of Cancer trial 62931 | 2007 | 351 | Adjuvant doxorubicin + ifosfamide + lenograstim | Observation | Macroscopically resected grade II-III sarcoma, no metastases | Relapse-free survival (RFS) | 5-year RFS 52% in both arms; OS 64% vs 69% (no significant difference). | No survival advantage for adjuvant chemotherapy | Confirmed that routine adjuvant chemotherapy is not indicated for all high-grade STS; selection for chemotherapy should be individualized. | Journal of Clinical Oncology (abstract 10008) |
| Italian Cooperative Trial | Italian randomized cooperative trial of adjuvant chemotherapy | 2001 | 104 | Epirubicin + ifosfamide | Observation | Patients with high-grade or recurrent extremity sarcoma | Disease-free survival (DFS), overall survival | Median DFS 48 vs 16 months (p=0.04); median OS 75 vs 46 months (p=0.04). 5-year OS 66% vs 46% (p=0.04). | Absolute OS benefit 13% at 2 years, 19% at 4 years. | Supports use of adjuvant anthracycline/ifosfamide in high-risk extremity STS. | Journal of Clinical Oncology |
| SU2C-SARC032 | Stand Up To Cancer-Sarcoma Alliance 032 | 2024 | Not specified in extract (reference Mowery 2024) | Neoadjuvant pembrolizumab + RT followed by adjuvant pembrolizumab + surgery | RT + surgery | Stage III soft tissue sarcoma of extremity (including UPS, MFS, ddLPS, pleomorphic LPS) | Not specified in extract | Improved event-free survival (results not presented in detail in NCCN text; cited as a positive trial leading to new recommendation) | None reported in NCCN extract | Added as preferred neoadjuvant/adjuvant regimen for UPS-related sarcomas (limb girdle/extremity UPS/MFS/ddLPS/pleomorphic liposarcoma) [SARC-G 1 of 14]. | Lancet |
| PALETTE | Pazopanib for metastatic soft-tissue sarcoma | 2012 | 369 | Pazopanib | Placebo | Metastatic non-lipogenic STS after failure of at least one anthracycline-based regimen | Progression-free survival (PFS) | Median PFS 4.6 months vs 1.6 months (HR not explicitly given, p<0.0001). OS 12.5 vs 11 months (p=0.25, not significant). | Health-related quality of life did not improve or decline. | Pazopanib is a standard option for advanced/metastatic non-lipogenic STS after anthracycline failure. | Lancet |
| ERIBULIN vs DACARBAZINE (Phase 3) | Eribulin versus dacarbazine in previously treated advanced liposarcoma or leiomyosarcoma | 2016 | 452 | Eribulin | Dacarbazine | Advanced liposarcoma (LPS) or leiomyosarcoma (LMS) after prior anthracycline-based therapy | Overall survival (OS) | Median OS 13.5 vs 11.5 months; HR 0.77 (95% CI 0.62–0.95, p=0.017). Benefit was limited to LPS subgroup. | None reported in NCCN extract. | Eribulin is a category 1 option for advanced liposarcoma and category 2A for other STS subtypes. | Lancet |
| TRABECTEDIN vs DACARBAZINE | Efficacy and safety of trabectedin or dacarbazine for metastatic liposarcoma or leiomyosarcoma after failure of conventional chemotherapy | 2016 | 518 (Demetri 2016) | Trabectedin | Dacarbazine | Metastatic LPS or LMS after prior anthracycline-based therapy | PFS (assessed by independent review) | Median PFS 4.2 vs 1.5 months (HR 0.55; 95% CI not given, p<0.0001). OS not significantly different (HR for death not reported). | Response rate, safety. | Trabectedin is a category 1 recommendation for LPS and LMS, and category 2A for other STS subtypes. | Journal of Clinical Oncology |
| Nirogacestat in DESMOID (DeFi) | Nirogacestat, a gamma-secretase inhibitor for desmoid tumors | 2023 | Not specified in extract (Gounder 2023) | Nirogacestat | Placebo | Progressive desmoid tumors | Progression-free survival (not specified in extract) | Nirogacestat improved PFS per investigator; results reported as positive (category 1 recommendation). | Spontaneous regression in up to 20% of observation arm. | Nirogacestat added as preferred systemic therapy for desmoid tumors (category 1). | New England Journal of Medicine |
| Sorafenib in DESMOID | Sorafenib for advanced and refractory desmoid tumor | 2018 | 50 (est.) | Sorafenib | Placebo (crossover) | Advanced refractory desmoid tumors | Not specified in extract | Objective response rate and PFS benefit; results led to category 1 recommendation. | None reported in NCCN extract. | Sorafenib is a preferred systemic therapy for desmoid tumors (category 1). | New England Journal of Medicine |
| STRASS | Preoperative radiotherapy plus surgery versus surgery alone for patients with primary retroperitoneal sarcoma (EORTC-62092) | 2020 | 266 | Neoadjuvant RT (50.4 Gy) + surgery | Surgery alone | Primary localized retroperitoneal sarcoma | Abdominal recurrence-free survival (ARFS) | Median ARFS 4.5 vs 5.0 years; HR 1.01 (p=0.95). No significant difference. Exploratory analysis suggested benefit in liposarcoma subgroup. | Common grade 3-4 adverse events: lymphopenia (77%), anemia (12%), hypoalbuminemia (12%) in RT+surgery group. | Neoadjuvant RT should not be considered standard of care for all retroperitoneal STS; may be considered in selected high-risk patients (e.g., liposarcoma). | Lancet Oncology |
| Pexidartinib in TGCT (ENLIVEN) | Pexidartinib versus placebo for advanced tenosynovial giant cell tumor (ENLIVEN) | 2019 | 120 (est.) | Pexidartinib | Placebo | Advanced tenosynovial giant cell tumor (TGCT) not amenable to surgery | Overall response rate (ORR) at week 25 | ORR 38% vs 0% (p<0.0001) per independent review. | Improvement in range of motion, pain, and quality of life. | Pexidartinib is category 1 recommendation for TGCT/PVNS; requires REMS due to hepatotoxicity. | Lancet |
| Vimseltinib in TGCT (MOTION) | Vimseltinib versus placebo for tenosynovial giant cell tumour (MOTION) | 2024 | 111 (est.) | Vimseltinib | Placebo | Advanced TGCT not amenable to surgery | ORR at week 25 | Significantly improved ORR; results led to category 1 recommendation. | None reported in NCCN extract. | Vimseltinib is a preferred systemic therapy for TGCT. | Lancet |
Clinical PearlsClick to collapse
- Pearl 1: Multidisciplinary management by a sarcoma expert team is mandatory before initiating any treatment; adherence to NCCN guidelines is associated with improved survival.
- Pearl 2: Preoperative RT is preferred over postoperative RT for extremity STS due to lower total dose (50 Gy vs 66 Gy), smaller fields, and less late toxicity, but carries a higher risk of acute wound complications, especially in lower extremity tumors.
- Pearl 3: Surgery alone (with close observation) is reasonable for stage IA tumors resected with wide negative margins >1 cm or intact fascial plane; RT can be omitted for small (<5 cm), low-grade, superficial lesions.
- Pearl 4: For desmoid tumors, the first-line approach is often observation ('wait and see') due to spontaneous regression in up to 20% of patients; progression, not just presence, should trigger intervention.
- Pearl 5: Pembrolizumab plus RT followed by adjuvant pembrolizumab is now a recommended neoadjuvant/adjuvant regimen for UPS-related sarcomas (limb girdle/extremity UPS, myxofibrosarcoma, dedifferentiated liposarcoma, pleomorphic liposarcoma) based on SU2C-SARC032.
- Pearl 6: NTRK gene fusion-positive sarcomas should receive targeted therapy (larotrectinib, entrectinib, repotrectinib) regardless of histologic subtype; these are effective even in heavily pretreated patients.
- Pearl 7: For retroperitoneal/intra-abdominal sarcomas, neoadjuvant RT can be considered in selected high-risk patients (especially liposarcoma), but the STRASS trial did not meet its primary endpoint; adjuvant RT is discouraged.
- Pearl 8: Biopsy technique is critical: core needle biopsy is preferred, placed along the future resection axis with minimal dissection and hemostasis; do not use fine-needle aspiration as the sole diagnostic method.
- Pearl 9: FDG-PET imaging (CT or MRI) is useful for staging high-risk sarcomas, assessing response to neoadjuvant therapy (≥40% reduction in SUVmax correlates with better outcomes), and distinguishing WDLPS from dedifferentiated liposarcoma.
- Pearl 10: Metastasectomy remains the historical standard for oligometastatic pulmonary disease and can be associated with long-term survival; however, SBRT, ablation, and embolization are acceptable alternatives.
- Pearl 11: For phyllodes tumors, surgical margin ≥1 cm is critical; mastectomy is often needed for malignant phyllodes to reduce local recurrence. Adjuvant RT should be considered for high-risk features (mitoses >30/10 HPF, size >10 cm, malignant heterologous elements).
- Pearl 12: In rhabdomyosarcoma, adult patients should be managed with pediatric-inspired multidisciplinary protocols; systemic therapy for non-pleomorphic RMS differs from standard STS - use VAC, VAI, or VDC-IE regimens.
Special SituationsClick to collapse
Previous unplanned excision of extremity/body wall/head/neck sarcoma
Failure to obtain oncologically appropriate margins (extremity/truncal/head/neck)
Fungating, necrotic, bleeding, and/or super-infected tumors
Retroperitoneal/intra-abdominal sarcoma with R1 or R2 resection
Desmoid tumor in patients with familial adenomatous polyposis (FAP) or Gardner syndrome
Rhabdomyosarcoma in adults: non-pleomorphic subtypes (alveolar, embryonal, spindle cell/sclerosing)
Rhabdomyosarcoma in adults: pleomorphic RMS
Atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDLPS) of extremity/trunk/abdominal wall
Borderline phyllodes tumor of the breast
Malignant phyllodes tumor of the breast
Isolated limb perfusion/infusion for unresectable extremity STS
Primary sarcoma with synchronous regional nodal metastatic disease
Guidelines ResourcesClick to collapse
NCCN Clinical Practice Guidelines in Oncology: Soft Tissue Sarcoma (Version 4.2026)
AJCC Cancer Staging Manual, 8th Edition (2017)
WHO Classification of Tumours of Soft Tissue and Bone, 5th Edition (2020)
Protocol for the Examination of Specimens from Patients with Soft Tissue Tumors (2017)
Radiation Therapy for Treatment of Soft Tissue Sarcoma in Adults: Executive Summary of an ASTRO Clinical Practice Guideline
Management of Primary Retroperitoneal Sarcoma (RPS) in the Adult: A Consensus Approach
Extremity DefinitionClick to collapse
Soft tissue sarcomas (STS) of the extremity, body wall, and head/neck are a heterogeneous group of malignant mesenchymal tumors arising in the limbs, trunk, and craniofacial regions. They account for the majority of STS, with the extremity being the most common primary site (43%), followed by trunk (10%) and head/neck (9%) [6]. STS are derived from connective tissues including fat, muscle, nerve sheaths, blood vessels, and other mesenchymal structures. More than 50 histologic subtypes are recognized [1]. These tumors have a propensity for hematogenous spread, most commonly to the lungs [MS-2]. The management requires multidisciplinary expertise and adherence to evidence-based guidelines to optimize outcomes [8].
Extremity SubtypesClick to collapse
The histologic subtypes of extremity/body wall/head and neck STS are numerous and include adipocytic tumors (e.g., liposarcomas: atypical lipomatous tumor/well-differentiated, dedifferentiated, myxoid, pleomorphic), fibroblastic/myofibroblastic tumors (e.g., myxofibrosarcoma, low-grade fibromyxoid sarcoma, sclerosing epithelioid fibrosarcoma, dermatofibrosarcoma protuberans), so-called fibrohistiocytic tumors (e.g., tenosynovial giant cell tumor, deep fibrous histiocytoma), smooth muscle tumors (leiomyosarcoma), vascular tumors (angiosarcoma, epithelioid hemangioendothelioma), pericytic tumors, chondro-osseous tumors, peripheral nerve sheath tumors (malignant peripheral nerve sheath tumor), and tumors of uncertain differentiation (e.g., synovial sarcoma, epithelioid sarcoma, alveolar soft part sarcoma, clear cell sarcoma, extraskeletal myxoid chondrosarcoma, desmoplastic small round cell tumor, PEComa, undifferentiated sarcoma) [ST-1 to ST-3]. The most common subtypes in adults include undifferentiated pleomorphic sarcoma, liposarcoma, leiomyosarcoma, and synovial sarcoma.
Extremity Molecular PathogenesisClick to collapse
Extremity STS harbor characteristic genetic aberrations. Recurrent chromosomal translocations include SS18::SSX1/SSX2 in synovial sarcoma, FUS::DDIT3 or EWSR1::DDIT3 in myxoid liposarcoma, EWSR1::ATF1/CREB1 in clear cell sarcoma, ASPL::TFE3 in alveolar soft part sarcoma, COL1A1::PDGFB in dermatofibrosarcoma protuberans, FUS::CREB3L2 in low-grade fibromyxoid sarcoma, and EWSR1::NR4A3 in extraskeletal myxoid chondrosarcoma [SARC-C 2-4]. Well-differentiated/dedifferentiated liposarcoma shows amplification of 12q13-15 including MDM2 and CDK4. Leiomyosarcoma has complex karyotypes. MPNST is associated with NF1, CDKN2A, and EED/SUZ12 alterations [SARC-C 4]. NTRK-rearranged spindle cell neoplasms are an emerging entity [SARC-C 4]. These markers are identified via FISH, PCR, or NGS; NGS may identify actionable mutations for clinical trials or immunotherapy [SARC-C 1].
Extremity EpidemiologyClick to collapse
In 2022, an estimated 13,190 new STS cases were diagnosed in the United States with 5,130 deaths [1]. Extremity STS accounts for 43% of all STS, trunk 10%, head and neck 9% [6]. Incidence is underestimated, especially prior to GIST inclusion [MS-2]. Prior radiation therapy is a known risk factor [2-4]. Five-year survival varies by stage and histology; localized disease has better survival than metastatic disease.
Extremity Risk FactorsClick to collapse
Risk factors include prior therapeutic radiation [2-4], chemical exposures (e.g., herbicides such as Agent Orange) [5], and genetic predisposition syndromes: Li-Fraumeni (germline TP53; STS incidence 12–21% [17-19]), neurofibromatosis type 1 (NF1; ~5% develop STS, mostly MPNST [30,31]), hereditary retinoblastoma (RB1; increased risk, especially leiomyosarcoma [11,29]), Lynch syndrome, and familial adenomatous polyposis (FAP) [9-13]. Additional factors: older age, but specific quantitative strengths are not provided in the guideline.
Retroperitoneal DefinitionClick to collapse
Retroperitoneal/intra-abdominal soft tissue sarcomas (STS) are malignant mesenchymal tumors arising in the retroperitoneal space or intra-abdominal cavity. They account for approximately 15% of all STS [6]. Common histologies include liposarcoma (well-differentiated/dedifferentiated) and leiomyosarcoma. These tumors often present as large masses and have a propensity for local recurrence and metastasis to liver and peritoneum rather than the lungs [MS-2]. Multidisciplinary management is essential, and neoadjuvant therapy may be considered to facilitate resection [RETSARC-1].
Retroperitoneal SubtypesClick to collapse
The main histologic subtypes of retroperitoneal/intra-abdominal STS include liposarcoma (well-differentiated liposarcoma [WDLPS], dedifferentiated liposarcoma [ddLPS]), leiomyosarcoma, and less commonly solitary fibrous tumor, malignant peripheral nerve sheath tumor, and undifferentiated sarcoma. WDLPS and ddLPS are the most common, often showing amplification of MDM2 and CDK4 [SARC-C 2]. Leiomyosarcoma arises from smooth muscle, often of vascular origin. Other subtypes include desmoid tumors (covered separately) and gastrointestinal stromal tumors (GIST, covered in separate guideline).
Retroperitoneal Molecular PathogenesisClick to collapse
Well-differentiated and dedifferentiated liposarcomas share supernumerary ring chromosomes and giant marker chromosomes with amplification of region 12q13-15, including MDM2, CDK4, HMGA2, SAS, and GLI [SARC-C 2]. Leiomyosarcoma has complex genomic alterations without specific recurrent translocations; the guideline previously listed unknown aberrations for leiomyosarcoma but removed that entry in the update [SARC-C 4 deletions]. Other retroperitoneal sarcomas may have specific fusions (e.g., solitary fibrous tumor with NAB2::STAT6 [SARC-C 4]).
Retroperitoneal EpidemiologyClick to collapse
Retroperitoneal STS accounts for 15% of all STS [6]. The true incidence is not separately reported in the guideline. These tumors are often large at diagnosis and have a high local recurrence rate after surgery. Systemic therapy is considered for high-risk or unresectable disease [RETSARC-2].
Retroperitoneal Risk FactorsClick to collapse
Risk factors are similar to those for STS in general: prior radiation therapy [2-4], chemical exposures [5], and genetic syndromes such as Li-Fraumeni (TP53), neurofibromatosis, and hereditary retinoblastoma [9-13]. Specific risk factors for retroperitoneal subtypes are not detailed in the guideline.
Desmoid DefinitionClick to collapse
Desmoid tumors, also known as aggressive fibromatoses, are unique mesenchymal neoplasms characterized by well-circumscribed, locally invasive fibroblastic proliferation. They are non-metastasizing but can cause significant morbidity due to local invasion and high recurrence rates [MS-30]. Desmoids are often associated with familial adenomatous polyposis (FAP) and Gardner syndrome, with CTNNB1 or APC mutations [DESM-1]. They can arise in intra-abdominal, abdominal wall, trunk/extremity, or head/neck locations.
Desmoid SubtypesClick to collapse
Desmoid tumors are classified by anatomic location: intra-abdominal, abdominal wall, pelvic, trunk/extremity, head/neck, intrathoracic, and retroperitoneal [DESM-4]. Histologically, they are composed of uniform spindle cells with variable collagen deposition. They are not further subclassified into distinct histologic subtypes, but sporadic and FAP-associated forms exist. Mutations in CTNNB1 (encoding β-catenin) are found in about 85% of sporadic cases, with three hotspots (41A, 45F, 45P) [310].
Desmoid Molecular PathogenesisClick to collapse
Sporadic desmoid tumors frequently harbor activating mutations in CTNNB1 (β-catenin gene) at codons 41 and 45, leading to Wnt pathway activation [310]. Trisomies 8 and 20, and loss of 5q21 (including APC) are also common [SARC-C 3]. In patients with FAP, germline APC mutations predispose to desmoids, often with additional somatic CTNNB1 mutations [310-312]. The CTNNB1 mutation 45F is associated with a higher risk of recurrence [310,313]. Molecular testing via mutation analysis can aid diagnosis [SARC-C 3].
Desmoid EpidemiologyClick to collapse
Desmoid tumors occur in 7.5% to 16% of patients with FAP [21-24]. The median age at diagnosis in FAP patients is 31 years, with intra-abdominal (53%) and abdominal wall (24%) being the most common locations [24]. Sporadic desmoids are rare; precise incidence is not provided. Spontaneous regression has been reported in up to 20% of patients [DESM-2 footnote e].
Desmoid Risk FactorsClick to collapse
Risk factors for desmoid tumors include FAP (APC mutation), positive family history of desmoids, prior abdominal surgery, and specific APC mutation sites [24]. For sporadic tumors, CTNNB1 mutations are very common, but the inciting factor is unknown. Female sex and pregnancy are known associations for abdominal wall desmoids, but this is not explicitly stated in the guideline.
Pleomorphic Rms DefinitionClick to collapse
Pleomorphic rhabdomyosarcoma (RMS) is a high-grade, aggressive subtype of rhabdomyosarcoma that occurs predominantly in adults. It is distinguished from non-pleomorphic RMS (alveolar, embryonal) by its complex genetic alterations and poor prognosis. According to the NCCN Guidelines, pleomorphic RMS should be treated like high-grade soft tissue sarcoma, using systemic therapy options from the STS algorithm [RMS-1]. It is not to be confused with anaplastic variant in children.
Pleomorphic Rms SubtypesClick to collapse
Pleomorphic RMS is a histologic subtype of RMS. The guideline does not further subdivide pleomorphic RMS; it is considered a distinct entity from alveolar, embryonal, and spindle cell/sclerosing RMS [RMS-1]. It is characterized by marked cytologic atypia and pleomorphism.
Pleomorphic Rms Molecular PathogenesisClick to collapse
Pleomorphic RMS has complex genetic alterations without the characteristic PAX3/PAX7 fusions seen in alveolar RMS. The molecular pathogenesis is not detailed in the guideline, but it is noted that pleomorphic RMS should be treated with regimens appropriate for high-grade STS [RMS-1]. The guideline does not provide specific mutation data for this subtype.
Pleomorphic Rms EpidemiologyClick to collapse
Pleomorphic RMS is the least common RMS subtype and occurs predominantly in adults older than 50 years [374]. The incidence increases with age; in one study of 39 adult patients, pleomorphic histology accounted for 0%, 27%, and 60% in age groups 16–19, 20–49, and 50+, respectively [374]. Among adults with RMS, pleomorphic histology is more common than in children (19% vs 1%) and is associated with unfavorable sites and worse survival (5-year OS 27% in adults vs 63% in children) [372].
Pleomorphic Rms Risk FactorsClick to collapse
Risk factors for RMS in adults are not well-defined. Li-Fraumeni syndrome (TP53 mutation) is associated with an increased risk, particularly for RMS in children (55% of STS in TP53 carriers) [17]. Other genetic syndromes may contribute, but specific risk factors for pleomorphic RMS are not mentioned.
Non Pleomorphic Rms DefinitionClick to collapse
Non-pleomorphic rhabdomyosarcoma (RMS) includes alveolar, embryonal, and spindle cell/sclerosing subtypes. These occur more frequently in children and adolescents but also affect adults. They are characterized by specific genetic fusions (alveolar: PAX3::FOXO1 or PAX7::FOXO1; spindle cell/sclerosing: VGLL2-related fusions or MYOD1 mutation). Embryonal RMS has complex alterations. Multidisciplinary management involving pediatric expertise is strongly recommended [RMS-1].
Non Pleomorphic Rms SubtypesClick to collapse
Non-pleomorphic RMS comprises alveolar RMS (including solid variant), embryonal RMS (including botryoid and spindle cell variants), and spindle cell/sclerosing RMS (with VGLL2-related fusions, intraosseous, or MYOD1 mutation) [RMS-1]. Anaplastic features can be seen in up to 13% of RMS in younger patients [RMS-1 footnote e]. Alveolar RMS is associated with PAX3/PAX7 fusions, while embryonal RMS is typically fusion-negative with complex karyotypes.
Non Pleomorphic Rms Molecular PathogenesisClick to collapse
Alveolar RMS harbors recurrent chromosomal translocations: t(2;13)(q35;q14) producing PAX3::FOXO1, t(1;13)(p36;q14) producing PAX7::FOXO1, and t(X;2)(q13;q35) producing PAX3::AFX [SARC-C 2]. Embryonal RMS shows complex alterations involving multiple genes including MYOD1, KRAS, HRAS, TP53, NF1, NRAS, PIK3CA, FBXW7, FGFR4, and BCOR [SARC-C 2]. Spindle cell/sclerosing RMS may have VGLL2-related fusions or MYOD1 mutation, and intraosseous variants may have specific alterations (not detailed). The presence of PAX3::FOXO1 versus PAX7::FOXO1 has prognostic implications in metastatic disease [37].
Non Pleomorphic Rms EpidemiologyClick to collapse
RMS is the most common STS of children and adolescents, but less common in adults [MS-1]. In adults, non-pleomorphic RMS (alveolar, embryonal) is also seen. The incidence in adults is lower than in children; 5-year OS for adult RMS is approximately 27% compared to 63% for children [372]. Among adult RMS, non-pleomorphic subtypes are less frequent than pleomorphic. The guideline does not provide specific incidence rates for each non-pleomorphic subtype.
Non Pleomorphic Rms Risk FactorsClick to collapse
Li-Fraumeni syndrome (TP53 mutation) is a known risk factor for RMS, particularly embryonal and alveolar in children [17]. Other syndromes such as neurofibromatosis and Beckwith-Wiedemann may be associated, but not detailed in this guideline. No specific environmental risk factors are mentioned.
Alt Wdlps DefinitionClick to collapse
Atypical lipomatous tumor (ALT) and well-differentiated liposarcoma (WDLPS) are low-grade adipocytic neoplasms. ALT is the term used for superficial locations (extremity, abdominal wall, trunk), while WDLPS is used for deep-seated tumors (retroperitoneum, paratesticular). Both are characterized by amplification of 12q13-15 including MDM2 and CDK4. They have no metastatic potential unless dedifferentiation occurs. Management involves surgical resection with oncologically appropriate margins; radiation is reserved for selected cases [ALT/WDLPS-1].
Alt Wdlps SubtypesClick to collapse
The entity includes ALT (extremity, trunk, abdominal wall) and WDLPS (retroperitoneum, paratesticular, and other deep sites). When dedifferentiation is present, it is classified as dedifferentiated liposarcoma and treated as a high-grade sarcoma [ALT/WDLPS-1]. Histologically, ALT/WDLPS shows adipocytic proliferation with variation in cell size and nuclear atypia, often with fibrous septa and lipoblasts.
Alt Wdlps Molecular PathogenesisClick to collapse
ALT/WDLPS is characterized by supernumerary ring chromosomes and giant marker chromosomes derived from amplification of the 12q13-15 region, leading to overexpression of MDM2, CDK4, HMGA2, SAS, and GLI [SARC-C 2]. This amplification is detectable by FISH or NGS and is a diagnostic hallmark, differentiating ALT/WDLPS from benign lipomas and other liposarcomas. Dedifferentiated liposarcoma maintains the same amplification but with additional genomic complexity.
Alt Wdlps EpidemiologyClick to collapse
ALT/WDLPS is one of the most common subtypes of liposarcoma. It occurs most frequently in the retroperitoneum and extremities. The guideline does not provide specific incidence numbers, but it is more common than pleomorphic liposarcoma. It has a favorable prognosis unless dedifferentiation occurs.
Alt Wdlps Risk FactorsClick to collapse
Risk factors for ALT/WDLPS are not specifically identified in the guideline. General STS risk factors such as prior radiation and genetic syndromes may apply, but no strong associations are noted.
Borderline Phyllodes DefinitionClick to collapse
Borderline phyllodes tumor of the breast is a fibroepithelial neoplasm with intermediate malignant potential, characterized by leaf-like stromal growth and variable cellular atypia, mitotic activity, and stromal overgrowth. It is distinct from benign and malignant phyllodes tumors. Management involves surgical excision with negative margins (≥1 cm) and consideration of adjuvant radiation for high-risk features [PHYLLSARC-1].
Borderline Phyllodes SubtypesClick to collapse
Phyllodes tumors are classified as benign, borderline, or malignant based on histologic features including stromal cellularity, atypia, mitotic rate, stromal overgrowth, and margin status. Borderline tumors have intermediate features, such as moderate atypia, mitotic count of 5–9 per 10 high-power fields, and pushing margins [PHYLLSARC-1]. The guideline does not further subdivide borderline phyllodes.
Borderline Phyllodes Molecular PathogenesisClick to collapse
The molecular pathogenesis of borderline phyllodes tumors is not detailed in the NCCN guideline. Genetic counseling and testing are recommended for breast and sarcoma genes plus other inherited cancer genes consistent with family phenotype [PHYLLSARC-1 footnote a]. Specific alterations are not provided.
Borderline Phyllodes EpidemiologyClick to collapse
Phyllodes tumors are rare, representing less than 1% of breast neoplasms. The incidence of borderline phyllodes specifically is not given in the guideline. They occur in women of all ages, with a peak in the 40s. The guideline does not provide numerical data.
Borderline Phyllodes Risk FactorsClick to collapse
No specific risk factors for borderline phyllodes tumors are mentioned in the guideline. Genetic predisposition (e.g., Li-Fraumeni) may be considered based on family history [PHYLLSARC-1].
Malignant Phyllodes DefinitionClick to collapse
Malignant phyllodes tumor of the breast is a rare, aggressive fibroepithelial neoplasm characterized by overtly malignant stromal features, including marked atypia, high mitotic activity (>10 per 10 HPF), stromal overgrowth, and infiltrative margins. It can metastasize (most commonly to lung and bone) and requires multidisciplinary management. Treatment involves surgical resection with wide margins (≥1 cm), mastectomy often necessary, and consideration of adjuvant radiation and systemic therapy [PHYLLSARC-2].
Malignant Phyllodes SubtypesClick to collapse
Malignant phyllodes tumors are a high-grade subtype of phyllodes tumors. Features include mitoses >10 per 10 HPF, severe cellular atypia, stromal overgrowth, and malignant heterologous elements (e.g., liposarcoma, chondrosarcoma, osteosarcoma) [PHYLLSARC-2 footnote d]. The guideline does not further subclassify malignant phyllodes.
Malignant Phyllodes Molecular PathogenesisClick to collapse
The molecular pathogenesis of malignant phyllodes tumors is not detailed in the guideline. Genetic counseling and testing for breast and sarcoma genes are recommended [PHYLLSARC-2 footnote a]. The guideline does not list specific molecular aberrations.
Malignant Phyllodes EpidemiologyClick to collapse
Malignant phyllodes tumors are rare. The guideline does not provide incidence or mortality numbers. A multicenter retrospective study of 51 patients with metastatic malignant phyllodes reported that surgery of metastasis was independently associated with overall survival (HR 0.33; 95% CI 0.14–0.78) [PHYLLSARC-4A footnote q]. Lung, bone, and visceral metastases are common.
Malignant Phyllodes Risk FactorsClick to collapse
No specific risk factors are identified. Genetic syndromes (e.g., Li-Fraumeni) may be relevant based on personal/family history [PHYLLSARC-2 footnote a].