Impact of central nervous system (CNS) prophylaxis on the incidence and risk factors for CNS relapse in patients with diffuse large B-cell lymphoma treated in the rituximab era: a single centre experience and review of the literature

Central nervous system (CNS) prophylaxis for diffuse large B‐cell lymphoma (DLBCL) is controversial with even less evidence in the era of R‐CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone) chemotherapy. We reviewed the impact of CNS prophylaxis in DLBCL patients treated with R‐CHOP at a tertiary care centre over a 7‐year period. CNS prophylaxis was recommended for ‘higher risk’ patients and consisted of intrathecal methotrexate and/or high‐dose methotrexate. Of 214 patients 12·6% received CNS prophylaxis. With a median follow‐up of 27 months, eight patients (3·7%) developed CNS relapse (75% isolated to the CNS and 62·5% as parenchymal brain disease) at a median time of 17 months. Patients who did not receive CNS prophylaxis had lower events (2·7%) than those who did (11·1%). Half of the CNS relapses occurred in testicular lymphoma patients, 75% of whom had received CNS prophylaxis. In multivariate analysis, testicular involvement was the only significant prognostic factor for CNS relapse (hazard ratio 33·5, P < 0·001). In conclusion, CNS relapse in DLBCL appears to present as a later, more isolated parenchymal event and at a lower rate in the rituximab era compared with historical data. R‐CHOP may negate the need for CNS prophylaxis with the exception of testicular lymphoma.