Factors Influencing Physician Discretion to Administer CNS Prophylaxis in Diffuse Large B Cell Lymphoma: A Single Institution Retrospective Study.

INTRODUCTION/BACKGROUND: Central nervous system (CNS) relapse is an infrequent but serious and challenging complication of diffuse large B-cell lymphoma (DLBCL) that carries a dismal prognosis. While several risk factors have been identified to stratify the risk for CNS relapse including the 2015 CNS internal Prognostic index (CNS-IPI), controversy still remains regarding the indication, timing, and method of CNS prophylaxis. The purpose of this study was to determine whether IT-MTX reduced the risk of CNS relapse, as well as treatment related and financial toxicity of CNS prophylaxis.

PATIENTS AND METHODS

In this retrospective study, we identified 194 patients with DLBCL who received care at Loma Linda University Cancer Center between January 2010- August 2022. We evaluated the efficacy, side effect profile, and financial toxicity of IT-MTX for CNS prophylaxis in patients with DLBCL.

RESULTS

In patients with intermediate to high CNS relapse risk (CNS-IPI 2-5) IT-MTX did not reduce the 1 year risk of CNS relapse (RR 1.1296, 95% CI 0.1933-6.6012, P = .08924). The median time to CNS relapse was longer in patients who had received IT-MTX (13.5 months) vs. those who did not (7 months). Thirty-eight (52.8%) patients reported adverse side effects of any kind as a result of IT-MTX administration, with 23.6% of patients developing grade 2 to 3 adverse events. The average cost for CNS-prophylaxis was estimated to be approximately $8,059.04 over a patient's treatment course, but as high as $20,140.

CONCLUSIONS

These findings suggest that IT-MTX has limited and potential transient effectiveness in preventing CNS relapse. Given the high rate of side effects and significant cost of IT-MTX, we recommend that clinicians carefully consider the risks and benefits of prophylaxis before prescribing IT-MTX for CNS-prophylaxis.