Treatment Patterns and Comparative Effectiveness in Elderly Diffuse Large B-Cell Lymphoma Patients: A Surveillance, Epidemiology, and End Results-Medicare Analysis

Background. The incidence of diffuse large B-cell lymphoma (DLBCL) occurs disproportionately in elderly patients. We evaluated real-world treatment patterns and outcomes in elderly DLBCL patients in the U.S. Materials and Methods. A retrospective cohort analysis of 9,333 DLBCL patients from the linked Surveillance, Epidemiology, and End Results (SEER)-Medicare database was conducted. Patients were diagnosed between January 1,2000, and December 31, 2007; were aged >66 years, and were continuously enrolled in Medicare Part A and B in the year prior to diagnosis. Within 3 months of diagnosis, 4,565 (49%) received rituximab plus chemotherapy (R+chemo), 2,181 (23%) received chemotherapy only, and 467 (5%) received rituximab monotherapy (R-mono). Cox proportional hazards regression assessed overall survival between R+chemo versus chemotherapy only and R-mono versus no treatment. Results. Overall, 23% of patients received no treatment, and the proportion was higher among those aged. 80 years (33%). Patients receiving R+chemo were younger and more likely white compared with those receiving chemotherapy only. Patients receiving R-mono were older and more likely female compared with those not treated. In multivariate analysis, patients receiving chemotherapy only had a twofold increased mortality risk versus R+chemo, and this was confirmed in a subanalysis of patients aged >80 years. A 91% higher mortality risk was noted with receipt of fewer than six cycles versus six cycles of chemotherapy or chemoimmunotherapy. Patients receiving R-mono had a 69% decreased mortality risk compared with patients who were not treated. Conclusion. This real-world analysis of elderly DLBCL patients confirmed that 23% do not receive treatment. Overall survival is higher for patients receiving R+chemo and R-mono relative to chemotherapy only and no treatment, respectively. Suboptimal durations of therapy with curative intent (fewer than six cycles) were associated with poorer outcomes.