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Proton Pelvic Sarcoma — SCE Medical Oncology MCQ

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ModerateSarcomaProton Pelvic SarcomaSCE Medical Oncology

A 50-year-old woman with sarcoma asks about proton beam therapy for her pelvic chondrosarcoma. What specific advantage does proton therapy offer for pelvic sarcomas?

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Correct answer: C — Proton beam therapy allows dose escalation to radioresistant sarcomas (≥70 Gy) while reducing dose to adjacent critical structures (bladder, rectum, bowel, sacral nerves, bone marrow) compared with photon RT — particularly important for chondrosarcoma which requires high doses for control

Pelvic chondrosarcomas and sacral chordomas require high radiation doses (≥70 Gy RBE) for local control but are adjacent to dose-sensitive organs. Proton therapy's Bragg peak allows dose escalation to the tumour while significantly reducing dose to: bowel (reduces GI toxicity), bladder, sacral nerve roots (preserves continence/sexual function), and bone marrow (preserves haematopoietic reserve for potential future chemotherapy). The NHS England Proton Beam Therapy Programme provides this treatment at Christie/UCLH for appropriate sarcoma patients.

Reference: NICE; NHS England PBT Programme; ESMO 2024 Bone Sarcoma; DeLaney et al IJROBP 2009