Prognostic and therapeutic factors of gliosarcoma from a multi-institutional series.

The aims of this multicentre retrospective study were to identify prognostic or therapeutic factors impacting on overall survival in patients with gliosarcoma. The analysis included all patients treated for gliosarcoma between 1998 and 2014 in seven French academic centres. Seventy-five patients with a median age of 60 years (range from 23 to 79 years) were treated with a combination of surgery (n = 66), radiotherapy (adjuvant for 64 patients and exclusive for 8 patients) and temozolomide based chemotherapy (n = 58). Median follow-up was 12 months (range from 2 to 71 months). Two-year overall survival (OS) and disease free survival rates were 12 % (95 % CI 4-20 %) and 2 % (95 % CI 0-6 %), respectively. The median OS was 13 months. Treatment at recurrence consisted of chemotherapy (n = 38) (bevazicumab for 18 patients, repeat temozolomide for 10 patients), salvage surgery (n = 8) and radiochemotherapy (n = 1). In univariate analysis, younger age, higher total dose of radiotherapy, longer time to recurrence and treatment at recurrence significantly increased OS. In multivariate analysis, high total dose of radiotherapy (HR = 0.97, p = 0.007) and treatment at recurrence (HR = 0.28, p < 0.001) were favourable prognostic factors of OS. Radiotherapy at a minimum dose of 54 Gy and salvage treatment increased OS of gliosarcoma. Unlike glioblastoma, in our analysis, TMZ based chemotherapy was not associated with an improvement in OS compared to patients who received radiation therapy only.