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.