Racial disparity in diffuse large B-cell lymphoma survival.

Abstract

6569 Background: Although blacks have a lower risk of non-Hodgkin lymphoma (NHL) compared to whites, black non-Hodgkin lymphoma (NHL) patients experience worse survival than white patients. This study aims to examine in patients with diffuse large B-cell lymphoma (DLBCL), the most common subtype of NHL, how much of the racial disparity in survival can be explained by differences in certain demographic (age, sex and area-level education) and access-to-care-related (stage, treatment, health insurance status) factors. Methods: Our cohort included 3716 non-Hispanic white or black DLBCL patients aged 18-64, diagnosed in 2004-2005 from the National Cancer Database (NCDB), a nationwide, hospital-based cancer registry. The analysis included only HIV/AIDS-negative patients. Kaplan-Meier survival curves were drawn for blacks and whites. Cox proportional hazards model was fitted to estimate hazard ratios (HR) and the 95% confidence intervals (CI) for race with and without controlling for demographic factors (age, sex and area-level education), stage, treatment and health insurance status. Results: Black patients had a worse survival than white patients (5-year survival rate 66.6% in blacks vs. 73.3% in whites, log-rank test p-value = 0.0006). Without adjusting for other factors, blacks had a 34% higher risk of death compared to whites (crude HR=1.34, 95% CI =1.13-1.58). After adjusting for demographic factors including age, sex and area-level education, the HR reduced to 1.27 (95% CI=1.06-1.51). After further adjustment for stage, treatment and insurance status, the association disappeared (HR=1.03, 95% CI= 0.86-1.23). Conclusions: Demographic factors and access-to-care-related factors including stage, treatment and health insurance status fully explained the black-white racial disparity in DLBCL survival in this cohort. Our findings suggest that improvements towards timely diagnosis, appropriate treatment and other adequate access to health care measures could potentially eliminate the survival disparity between black and white DLBCL patients.