Central nervous system event in patients with diffuse large B-cell lymphoma in the rituximab era

Central nervous system (CNS) events, including CNS relapse and progression to CNS, are known to be serious complications in the clinical course of patients with lymphoma. This study aimed to evaluate the risk of CNS events in patients with diffuse large B-cell lymphoma in the rituximab era. We performed a retrospective survey of Japanese patients diagnosed with diffuse large B-cell lymphoma who underwent primary therapy with R-CHOP chemoimmunotherapy between September 2003 and December 2006. Patients who had received any prophylactic CNS treatment were excluded. Clinical data from 1221 patients were collected from 47 institutions. The median age of patients was 64 years (range, 15-91 years). We noted 82 CNS events (6.7%) and the cumulative 5-year probability of CNS events was 8.4%. Patients with a CNS event demonstrated significantly worse overall survival (P < 0.001). The 2-year overall survival rate after a CNS event was 27.1%. In a multivariate analysis, involvement of breast (relative risk [RR] 10.5), adrenal gland (RR 4.6) and bone (RR 2.0) were identified as independent risk factors for CNS events. We conclude that patients with these risk factors, in addition to patients with testicular involvement in whom CNS prophylaxis has been already justified, are at high risk for CNS events in the rituximab era. The efficacy and manner of CNS prophylaxis in patients for each involvement site should be evaluated further.