P11.63.B Thrombocytopenia limits the feasibility of salvage lomustine chemotherapy in recurrent glioblastoma: a secondary analysis of EORTC 26101

Abstract Background Chemotherapies used for the treatment of primary brain tumors frequently induce hematological toxicity. Thrombocytopenia represents main cause stopping chemotherapy Here we explored incidence, and consequences exposure survival, thrombocytopenia induced by lomustine at first recurrence glioblastoma. Methods We performed a retrospective analysis glioblastoma, its delivery, associations with outcome in phase II III parts EORTC 26101, randomized trial designed to define role versus bevacizumab their combination glioblastoma patients relapse. Results 225 were treated alone (median 1 cycle) (group 1) 283 plus 3 cycles) 2). Among cycle delays dose reductions toxicity, was leading cause. 129 group 187 2 experiencing least one episode thrombocytopenia, 36 93 had modified because thrombocytopenia. Lomustine discontinued 16 (7.1%) 38 (13.4%) 2. Patients O6-methylguanine DNA methyltransferase (MGMT) promoter-methylated experienced more interference study than without MGMT promoter methylation. On adjusted accounting major prognostic factors, modification positive factor overall this effect entirely driven methylation only. Conversely, associated inferior progression-free survival tumors, suggesting link insufficient exposure. Conclusion Drug-induced is limitation adequate salvage recurrent Its association suggests that mitigating allow enhanced drug methylated might improve outcome.