Methotrexate based chemotherapy and deferred radiotherapy for primary central nervous system lymphoma (PCNSL): single institution experience

In the following study, we present our experience in the treatment of PCNSL patients using a multi-step schedule combining chemotherapy and deferred radiotherapy. Patients were treated with two modified M-BACOD cycles and then differently according to radiological response For PR, SD and PD patients, chemotherapy was interrupted and radiotherapy initiated immediately (45 Gy Whole-brain RT). With CR patients, chemotherapy was continued with a combination of HMTX, VCZ, PCB and HD Ara-C up to a total of nine cycles. In 36 patients suitable for evaluation (2 patients had undergone tumour resection): 69.4% (25 of 36) had a complete response (CR), 19.4% (7 of 36) had a partial response(PR), 8.3% (3 of 36) had stable disease(SD), and 2.7% (one of 36) had progressive disease (PD). The PR, SD and PD patients were immediately treated by radiotherapy. In this cohort of patients, we observed 6 CR, 4 PR and 2 PD, respectively, following radiotherapy. At first relapse, a total of 16 CR patients were treated by radiotherapy for a total dose of 45 Gy. The OS was 42.1 months for the entire group of patients. In CR patients treated at the moment of recurrence by salvage radiotherapy, the TTP (time lasting from histological diagnosis until recurrence of disease before RT) was 28.3 months, with a 43.4% of disease free patients observed at 2 years. The median disease-free time observed after complete response to radiotherapy was 10.5 months. In 16 patients (34%), further progression of disease was observed following radiotherapy. Two patients developed extra-CNS disease in the breast and testis. When taking into account the patients with radiotherapy delayed at recurrence, the OS was 48 months and the survival rates were 70% and 60% at 2 years and 5 years, respectively.