FRONTLINE THERAPY RESULTS IN UNSELECTED PRIMARY CNS LYMPHOMA PATIENTS WITHOUT CONSOLIDATION HD CHEMOTHERAPY FOLLOWED BY AUTOLOGOUS STEM CELL TRANSPLANTATION

Abstract

Introduction: Therapy results from large prospective clinical trials in primary CNS lymphoma (PCNSL) are influenced by restrictive inclusion and exclusion criteria. Herein we present frontline therapy results in unselected patients with PCNSL based on retrospective analysis from single center database over the past 17 years, when consolidation high-dose chemotherapy with autologous stem cell transplantation (ASCT) was not a standard therapeutic approach. Methods: Between 2000 and 2017 we register 79 patients with newly diagnosed PCNSL, median age 64 years (31 – 84). Frontline regimen for patients ≤ 70 years was 5-7x MPV +/- rituximab. Consolidation therapy conceded 2 cycles of cytarabine for selected patients in complete remission instead whole brain radiation therapy (WB RT) up to 45 Gy. None of the patients had consolidation HD chemotherapy with ASCT. Results: Chemotherapy was administered to 72 patients (91 %), in 71 % (51 pts.) MPV regimen +/- rituximab. The rest of the patients had single agent methotrexate or cytarabine or WB RT. Only 35 patients completed at least 5 cycles of MPV-based chemotherapy, the others failed to complete because of unacceptable toxicity or progressive disease. Median OS in the whole unselected cohort was 38 months, 2-year PFS was 40 % and median PFS 14 months. Response rates were evaluated only in the subgroup of 35 patients who completed at least 5 MPV-based chemotherapy. Median age was 57 years (31 - 70), ORR was 80 %, progression was seen in 5 patients (14%), 2 were unable to assess. In this subgroup of relatively fit patients 2-year PFS was 45 % and 2-year OS was 55 %. 10 patients in CR after frontline therapy did not undergo WB RT consolidation, but received 2 courses of single agent cytarabine instead. 5 of them reached durable remission and in the other 5 late relapses occured with median PFS 31 months (12-72). Keywords: autologous stem cell transplantation (ASCT); primary CNS lymphoma (PCNSL).