NCOG-25. THROMBOCYTOPENIA LIMITS THE FEASIBILITY OF SALVAGE LOMUSTINE CHEMOTHERAPY IN RECURRENT GLIOBLASTOMA: A SECONDARY ANALYSIS OF EORTC 26101

Abstract BACKGROUND Thrombocytopenia represents the main cause of stopping chemotherapy for toxicity during treatment glioblastoma. Here we explored incidence and prognostic implications lomustine modification thrombocytopenia in recurrent METHODS We retrospectively analysed thrombocytopenia, its consequences delivery, associations with outcome phase II III parts EORTC 26101, a randomized trial to define role versus bevacizumab their combination RESULTS 225 patients were treated alone (median 1 cycle) (group 1) 283 plus 3 cycles) 2). 129 (57%) group 187 (66%) 2 experienced at least one episode thrombocytopenia; 36 (16%) 93 (33%) had modified thrombocytopenia. Lomustine was discontinued 16 (7.1%) 38 (13.4%) 2. Patients MGMT promoter-methylated glioblastoma more than tumors without promoter methylation. On adjusted analysis accounting major factors, induced by associated inferior progression-free survival (PFS) MGMTpromoter-methylated both groups, suggesting link insufficient exposure. This effect noted overall survival, too, but only patients. promoter-unmethylated who dose longer PFS this driven largely CONCLUSION Drug-induced is limitation adequate exposure Its association suggests that mitigating allow enhanced methylated might improve outcome.