Racial Disparities in Survival Outcomes of Diffuse Large B Cell Lymphoma: A Retrospective Cohort Study from 2000 to 2021

Introduction Diffuse Large B Cell Lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma (NHL), accounting for 25-30% of all cases of NHL. DLBCL is an aggressive disease that can be cured in up to 50% of the patients who achieve complete remission following treatment with first-line therapy. In this study, we described the effect of race/ethnicity on survival outcomes among patients with DLBCL in the United States. Methods We extracted data on patients with a primary diagnosis of DLBCL from the Surveillance, Epidemiology and End Results (SEER) Registry. These patients had a primary diagnosis of DLBCL. We excluded patients with missing or unknown deaths, and Kaplan-Meier methods were used to estimate 5-year survival rates. Cox proportional hazards regression was used for multi-variable modelling of the survival database. The difference between the observed number of events between each group was compared using a log-rank statistical test. Results Our analysis revealed 99,415 patients with DLCBL. 82.8% (82,356) of patients were white, 7.2% (7244) of patients were black, 0.6% (602) were American Indian/Alaska Native, and 9.3% (9213) were Asian or Pacific Islanders. The one and five-year survival by race/ethnicity was White (75.9%, 64.0%), Black (72.6%, 60.6%), American Indian/Alaska Native (72.6%,61.1%) and Asian/Pacific Islander (76.5%,63.5%). Race/ethnicity proved to be a predictor of worse outcomes, with Asian/Pacific Islander HR 0.96 (95% CI; 0.92-0.99, p = <0.001), Black HR 1.01 (95% CI; 0.98-1.04, p = 0.629), American Indian/Alaska Native HR 1.06 (95% CI; 0.95-1.18, p = 0.294). There was no survival disparity by sex, male, HR 1.00 (0.98-1.02) p = 0.93. Conclusion Race plays a significant role in survival outcomes, with certain races associated with improved outcomes in patients with DLBCL. Asian/Pacific Islanders demonstrated a statistically significant improved survival outcome compared to whites. Of note, there was no disparity in survival outcomes by sex.