A Systematic Review on the Role of Postoperative Radiotherapy in Pelvic Ewing Sarcoma.

Ewing Sarcoma of the pelvis has poorer outcomes than other anatomical sites, with complex anatomy often precluding resection with wide margins. The role of postoperative radiotherapy (RT) in improving outcomes remains undefined. A systematic review using Medline, Embase and Cochrane databases (1972-April 2024) evaluated postoperative RT's impact on local recurrence, event-free survival and overall survival. Twenty-nine retrospective studies (21 to 296 patients) met inclusion criteria, with 28 rated good quality. Seven of 14 studies showed improved local control with postoperative RT. Ten studies reported consistent but non-significant trends favoring postoperative RT for event-free survival. Nineteen studies reported mixed overall survival findings; the Euro-EWING 99 trial showed significantly improved 5-year survival (72% vs. 47%, p = 0.024), while others showed conflicting results. Postoperative RT should be considered for high-risk features including poor response to induction chemotherapy, large tumour volume (> 200 mL) and positive margins. Clinical trial participation should be encouraged. Trial Registration: PROSPERO registration number: CRD42021291665.