Results of methotrexate-etoposide-ifosfamide based regimen (M-EI) in osteosarcoma patients included in the French OS2006/sarcome-09 study.

Background: In most countries, reference chemotherapy for osteosarcoma is MAP regimen (M = high-dose methotrexate, AP = doxorubicin-cisplatinum). In France, the standard preoperative chemotherapy for children/adolescents combines M and etoposide-ifosfamide (EI), based on the OS94-trial. We report the safety and efficacy results of patients ≤25 years treated with preoperative M-EI regimen enroled in the French OS2006-study, between 2007 and 2014.

Methods: Treatment comprised preoperative chemotherapy with the 7 M-courses and 2 EI-courses, then surgery and postoperative chemotherapy assigned by risk's groups: standard-risk (good histological response without metastases) received 12 M-courses, 3 EI-courses; high-risk (poor histologic response, initial metastases or unresectable primary) received 5 M-courses alternated with 5 AP-courses. 253 patients were randomised to receive (n = 128) or not (n = 125) zoledronate.

Results: 409/522 patients enroled in the OS2006 study who received preoperative M-EI were analysed. Median age was 14.3 years (4.7-24.5), with 55 patients aged 18-25 years. Primary tumour location was limb in 383 patients (94%) and 85 (21%) presented metastases. Median chemotherapy duration was 37.4 weeks. 381 (96%) patients underwent surgery, 258 patients (65%) had a good histologic response. 187/324 patients (58%) with localised disease did not receive doxorubicin nor cisplatinum. Toxicity was evaluated in the randomised study: most patients experienced ≥1 severe toxicity (grade IV haematological or grade III/IV extra-haematological). Median follow-up was 4.8 years, and 168 patients had events. Five-year event-free survival was 56% (95% CI, 51-62%) and overall survival 71% (66-76%).

Conclusion: M-EI regimen/strategy was feasible for patient aged ≤25 years with survival rates are comparable to those obtained with MAP regimen.