Association between local treatment modalities and event-free survival, overall survival and local recurrence in patients with localized Ewing Sarcoma. Report from the Ewing 2008 trial
Menée à partir de données multicentriques portant sur 863 patients traités par chimiothérapie d'induction pour un sarcome d'Ewing de stade localisé, cette étude analyse la survie sans événement, la survie globale et la récidive locale en fonction du traitement local reçu (chirurgie, radiothérapie ou une combinaison des deux)
Background: Local treatment is a crucial element in the standard of care for Ewing sarcoma (EWS). While systemic treatment is improved in randomized clinical trials, local treatment modalities are discussed controversially. We analyzed the association between local therapy and event-free survival (EFS), overall survival (OS) and local recurrence (LR) in prospectively collected data of patients with localized EWS. Patients and Methods: We analyzed data from the international Ewing 2008 study registered between 2009 and 2019 in 117 centers. After induction chemotherapy, patients received surgery, radiotherapy, or a combination thereof. We performed Cox regression, conducted propensity score weighted sensitivity analysis and performed subgroup analyses. Hazard ratios (HRs) and 95% Confidence Intervals are reported. Results: We included 863 patients with localized EWS (surgery alone: 331, combination therapy: 358, definitive radiotherapy: 174). In patients treated with combination therapy compared to surgery alone, EFS HR was 0.84 (0.57-1.24; p=0.38), OS HR was 0.84 (0.57-1.23; p=0.41) and LR HR was 0.58 (0.26-1.31; p=0.19). Hazards of any event were increased in patients treated with definitive radiotherapy compared to surgery only, HR 1.53 (1.02-2.31; p=0.04). Patients with poor response to chemotherapy benefitted from combination therapy over definitive surgery with an EFS HR 0.49 (0.27-0.89; p=0.02). Patients with pelvic tumors benefitted from combination therapy over surgery only regarding LR, HR 0.12 (0.02-0.72; p=0.02) Conclusions: Patients with poor response to chemotherapy benefitted from radiotherapy added to surgery. In the whole group, radiotherapy alone as opposed to surgery alone increased hazards of any event.