Impact of central nervous system (CNS) prophylaxis on the incidence of CNS relapse in patients with high-risk diffuse large B cell/follicular grade 3B lymphoma.

Although overall survival in diffuse large B cell lymphomas (DLBCL) has improved, central nervous system (CNS) relapse is still a fatal complication of DLBCL. For this reason, CNS prophylaxis is recommended for patients at high risk of CNS disease. However, no consensus exists on definition of high-risk patient and optimal CNS prophylaxis. Systemic high-dose methotrexate in combination with R-CHOP has been suggested as a potential prophylactic method, since methotrexate penetrates the blood-brain barrier and achieves high concentration in the CNS. In this retrospective analysis, we report treatment outcome of 95 high-risk DLBCL/FL grade 3B patients treated with R-CHOP or its derivatives with (N = 57) or without (N = 38) CNS prophylaxis. At a median follow-up time (51 months), CNS relapses were detected in twelve patients (12.6%). Ten out of twelve (83%) of CNS events were confined to CNS system only. Median overall survival after CNS relapse was 9 months. Five-year isolated CNS relapse rates were 5% in the prophylaxis group and 26% in the group without prophylaxis. These findings suggest that high-dose methotrexate-containing prophylaxis decreases the risk of CNS failure.