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STS Perioperative RT — SCE Medical Oncology MCQ

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ModerateSarcomaSTS Perioperative RTSCE Medical Oncology

A 55-year-old man has a synovial sarcoma of the thigh. FISH confirms the SS18 (SYT) rearrangement. He asks about the role of radiotherapy in limb sarcoma. What is the evidence for perioperative radiotherapy in soft tissue sarcoma?

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Correct answer: B — Perioperative radiotherapy (neoadjuvant or adjuvant) reduces local recurrence from ~30% to ~10-15% for high-grade deep STS >5 cm — neoadjuvant RT has a smaller field/lower dose but higher wound complications; adjuvant RT has a larger field/higher dose but fewer wound issues

The Canadian SR2 trial established that perioperative RT significantly reduces local recurrence in extremity STS. Neoadjuvant RT (50 Gy in 25 fractions → surgery at 4-6 weeks) has advantages: smaller field (only the tumour + margin, not the entire surgical bed), lower dose (50 vs 60-66 Gy), and allows tumour downstaging, but has higher wound complication rates (~35% vs ~17%). The choice between neoadjuvant and adjuvant RT depends on tumour characteristics, location and surgical planning.

Reference: ESMO 2024 STS; Canadian SR2 O'Sullivan et al Lancet 2002; NICE NG