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

ABSTRACT

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.