Limited efficacy of high-dose methotrexate to prevent the central nervous system relapse in patients with IVLBCL.

To evaluate the efficacy of high-dose methotrexate (HD-MTX, ≥1 g/m 2 ) for the prevention of central nervous system (CNS) recurrence in patients with intravascular large B-cell lymphoma (IVLBCL), we reviewed 51 patients with pathologically diagnosed untreated IVLBCL. In total, there were five cases of CNS relapse (9.8%), and the 12-month CNS relapse rate was 9.2%. No statistical difference in CNS relapse rate ( p  = 0.86) was observed between patients with and without HD-MTX ( n  = 20 and 31, respectively). Furthermore, the composite endpoint defined as either CNS and/or neurolymphomatosis relapse was not significant in terms of the administration of HD-MTX ( p  = 0.25). No significant predictor of CNS relapse was found. In conclusion, patients with IVLBCL are at high risk of CNS recurrence; however, HD-MTX administration may not be effective for CNS recurrence prophylaxis. Key pointsThe administration of HD-MTX for patients with untreated IVLBCL may not be effective for preventing CNS relapse.