Soft tissue sarcoma

Soft tissue sarcomas arise in supporting tissues such as fat, muscle, vessels and connective tissue. A painless enlarging lump can be significant; deep location, growth or recurrence after removal warrants assessment. Abdominal tumors may cause fullness or pain rather than a visible lump. Symptoms alone cannot distinguish sarcoma from a benign mass.

Imaging usually precedes biopsy: MRI defines many limb and trunk tumors, while CT is central for retroperitoneal disease. Image-guided core biopsy should be planned with the treating team, so the track and sampled area support later surgery. If a lump has already been removed unexpectedly, obtain the original scans, pathology slides and operation report before deciding on further treatment.

Expert pathology review integrates appearance, immunohistochemistry and selected molecular tests. MDM2 amplification can help classify certain lipomatous tumors; an SS18-related fusion supports synovial sarcoma. A broad sequencing report does not replace a reliable tissue diagnosis, and a gene alteration may be diagnostic without being a proven drug target.

This guide focuses on adult-type soft tissue sarcomas. GIST, uterine sarcomas and Ewing sarcoma have dedicated pathways, while childhood rhabdomyosarcoma requires a pediatric sarcoma team. Malignant peripheral nerve sheath tumors may also prompt assessment for NF1; unusually young age or a suggestive family history can justify genetic counseling.

Explore the relevant dedicated guide when the pathology identifies one of these entities.

Grade describes biological aggressiveness under the microscope; stage describes the extent of disease. Size, depth, site, margins and subtype also influence recurrence risk. Chest CT commonly checks for lung spread, but additional imaging is tailored: some subtypes need assessment beyond the lungs. Routine lymph-node surgery is not appropriate for every sarcoma.

Ask the team to distinguish localized and completely resectable disease from locally unresectable disease and distant metastases. A borderline operation may become feasible after selected preoperative treatment, but the probability of meaningful shrinkage and the risk of delaying surgery must both be discussed.

For operable localized disease, surgery aims for tumor-free margins while preserving useful function. Reconstruction and rehabilitation belong in the initial plan. A positive or uncertain margin may lead to further surgery or radiotherapy, depending on anatomy and risk; radiotherapy does not make an avoidable incomplete operation equivalent to a complete resection.

The 2026 ESTRO guideline, endorsed by ASTRO, favors preoperative radiotherapy when radiation is indicated for extremity or trunk-wall sarcoma. Decisions depend on local-recurrence risk and specialist review. Shorter radiation schedules and combinations with systemic drugs remain areas of investigation rather than universal replacements for established treatment.

Timing involves a tradeoff. Preoperative radiation generally treats a smaller area but increases wound-healing concerns; postoperative treatment can involve larger fields and more late stiffness, swelling or fibrosis. Low-risk tumors may not need radiation. Ask about wound care, joint function, nerve protection and the planned interval to surgery.

Retroperitoneal sarcoma grows behind the abdominal organs. Surgery may require removal of adjacent structures to achieve an appropriate oncological resection, with planning shaped by histology and organ function. The surgeon’s experience with this specific anatomical setting matters; an extremity-sarcoma plan cannot simply be transferred to the abdomen.

STRASS did not show an overall abdominal recurrence-free survival benefit from routine preoperative radiotherapy. Subsequent analyses suggest that selected liposarcoma groups may differ, but subgroup and nonrandomized findings do not establish radiation for everyone. Discuss the expected pattern of recurrence, the organs at risk and the rationale for any proposed radiation.

Chemotherapy is not obligatory after every sarcoma operation. It is considered selectively for higher-risk, chemotherapy-sensitive disease, taking account of the subtype, estimated distant-relapse risk, fitness and patient priorities. A predicted risk estimate helps a discussion; it cannot guarantee benefit for an individual.

SARC032 studied perioperative pembrolizumab with preoperative radiation and surgery in stage III extremity or limb-girdle undifferentiated pleomorphic sarcoma and dedifferentiated or pleomorphic liposarcoma. Two-year disease-free survival improved, with more serious toxicity. This is a subtype-specific treatment discussion, not evidence for giving immunotherapy to every localized sarcoma. Trial evidence, guideline adoption and local reimbursement should be checked separately.

For many advanced adult-type sarcomas, doxorubicin remains a first-line backbone. Adding ifosfamide can increase tumor shrinkage and delay progression but did not improve overall survival significantly in the pivotal randomized comparison, and toxicity increased. A combination may be reasonable when rapid shrinkage could relieve major symptoms or enable a local procedure; it is not automatically the better choice for everyone.

Leiomyosarcoma is an important exception to a one-size-fits-all approach. LMS04 showed longer survival with doxorubicin–trabectedin followed by trabectedin maintenance than with doxorubicin alone in previously untreated advanced leiomyosarcoma, at the cost of greater toxicity. This applies to the studied subtype and requires an assessment of marrow, liver and cardiac reserve.

A small number of metastases may prompt discussion of surgery, stereotactic radiation or ablation. Selection depends on whether all relevant disease can be controlled, the disease-free interval, progression elsewhere and expected function. Favorable outcomes in selected patients do not prove that every lung metastasis should be removed.

Later treatment may use a different chemotherapy, targeted drug or clinical trial. Prior response, cumulative anthracycline exposure, residual neuropathy and marrow or liver function matter as much as the list of available medicines. A change should answer a practical goal: shrink a threatening lesion, slow growth, relieve symptoms or reduce treatment burden.

Some uncommon subtypes have specific options: intravenous atezolizumab has a US indication for unresectable or metastatic alveolar soft part sarcoma from age two; nab-sirolimus is approved in the US for adults with locally advanced unresectable or metastatic malignant PEComa; crizotinib has an indication for qualifying ALK-positive inflammatory myofibroblastic tumors. These diagnoses should not be replaced by a generic “sarcoma” label.

A confirmed NTRK fusion can open a tumor-agnostic treatment pathway such as larotrectinib when its indication criteria are met. Protein staining or an unrelated NTRK mutation alone is not equivalent. Similarly, a general “immune-positive” result does not establish checkpoint-inhibitor benefit across every sarcoma subtype.

An important change concerns tazemetostat (Tazverik), previously listed for epithelioid sarcoma. Following a safety signal involving new blood cancers, the FDA’s withdrawal of approval became effective in June 2026. Older treatment lists can therefore be misleading. Do not stop or replace a prescribed treatment independently; ask the treating team about the current regulatory position and an alternative plan.

Afamitresgene autoleucel (Tecelra) is an engineered autologous T-cell receptor therapy, not a general CAR-T treatment for all solid tumors. The current US indication includes patients aged 12 or older with unresectable or metastatic synovial sarcoma after prior chemotherapy, with specified HLA-A*02 alleles and MAGE-A4 expression confirmed by approved or cleared companion tests. HLA-A*02:05P is a contraindication, so “HLA-A2 positive” alone is insufficient.

The pathway includes cell collection, manufacturing, lymphodepleting chemotherapy and infusion at a prepared treatment center. Risks include cytokine release syndrome, neurotoxicity, infection and prolonged low blood counts. Eligibility, manufacturing time and disease control while waiting must be assessed before travel or financial commitments. US approval does not establish availability in every country.

Follow-up considers both local recurrence and distant spread, with timing and imaging tailored to subtype, grade, site and prior therapy. New lumps, persistent cough, unexplained pain or declining function deserve assessment between scheduled visits. Rehabilitation, lymphedema care, pain management and psychological support are part of treatment, alongside cardiac or other late-effect monitoring when relevant.

For a second opinion, prepare the pathology report and slides or blocks, molecular results, original imaging with dates, operation and margin details, radiotherapy plans, and a treatment timeline with response and toxicity. Ask which uncertainty could change the next decision: diagnosis, resectability, treatment sensitivity or eligibility for a subtype-specific trial.