Comparison of standardized prophylactic high-dose and intrathecal methotrexate for DLBCL with a high risk of CNS relapse

The efficacy of high-dose methotrexate (HD-MTX) for central nervous system (CNS) relapse prophylaxis in patients with high-risk diffuse large B-cell lymphoma (DLBCL) is controversial. We compared the prophylactic effects of HD-MTX and intrathecal methotrexate (IT-MTX) on CNS relapse in high-risk DLBCL, in a multicenter retrospective study. A total of 132 patients with DLBCL at high risk of CNS relapse who received frontline chemotherapy and IT-MTX from 2003 to 2013 (n = 34) or HD-MTX from 2014 to 2020 (n = 98) were included. After a median follow-up of 52 months (range: 9–174), 11 patients had isolated CNS relapse: six (6.1%) in the HD-MTX group and five (14.7%) in the IT-MTX group. The median time until CNS relapse was 38 months (range: 11–122), and the cumulative incidence of CNS relapse at 3 years was 3.9% in the HD-MTX group and 6.1% in the IT-MTX group (P = 0.93). Similar results were obtained after adjusting for background factors using propensity score-matched analysis (4.5% HD-MTX vs. 7.6% IT-MTX, P = 0.84). The CNS relapse rate in HD-MTX-treated patients was equivalent to that in IT-MTX patients, demonstrating that HD-MTX was not superior to IT-MTX in preventing CNS relapse.