Immunochemotherapy or chemotherapy alone in primary central nervous system lymphoma: a National Cancer Database analysis

Debate remains over the role of rituximab, a large molecule with reduced central nervous system (CNS) penetration, in therapy for primary CNS lymphoma (PCNSL). Since 2013, the National Cancer Database has distinguished between chemotherapy and immunotherapy for frontline treatment. In this setting, rituximab would be the only standard frontline immunotherapy. We examined factors associated with the receipt of immunotherapy using a multivariate regression model for relative risk, with a random intercept to account for the hospital-specific treatment selection process. Patients were matched using a 1:1 propensity score to limit possible confounders, and overall survival (OS) was compared in the matched cohort. We identified 4691 patients with PCNSL diagnosed between 2013 and 2018. The use of immunotherapy has increased from 45% in 2013 to 76% in 2018. Immunotherapy use was associated with sociodemographic variables and local (hospital level) preference rather than clinical factors. The main factors associated with reduced use of immunotherapy included male sex, Black race or Hispanic ethnicity (compared with White non-Hispanic), HIV(+) status, treatment in a lower-volume hospital, and earlier year of diagnosis. We matched 2830 patients for the survival analysis. Receipt of immunotherapy was associated with a significantly better OS (hazard ratio [HR], 0.75; 95% confidence interval [CI], 0.67-0.83). There was heterogeneity according to age, because the advantage of immunotherapy was more pronounced for patients aged ≤75 years (HR, 0.71; 95% CI, 0.63-0.80) than for those older than 75 years (HR, 0.87; 95% CI, 0.70-1.08). Overall, our findings support the current trend toward rituximab use, although a nuanced approach should be adopted when treating older patients.