Racial disparities in the survival of patients with indolent non-Hodgkin lymphomas in the United States.

Abstract

There is a paucity of data regarding racial disparities in the survival of patients with indolent non-Hodgkin lymphomas (iNHL) in the contemporary time-period. Hence, we sought to determine whether racial disparities exist in the survival of patients with iNHLs in the US. We included 68 059 adult patients with follicular lymphoma (FL, n= 41 943), marginal zone lymphoma (MZL, n= 22 485), and lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (LPL/WM, n= 3631) who were diagnosed in the US between 2000 and 2017. Race was categorized as White, Black, Asian/Pacific Islander, or American Indian/Alaska Native (API/AI). The primary outcome was relative survival (RS), which was estimated using flexible parametric survival models. The RS estimates varied according to race and disease histology but were consistently lower for racial minorities, including those diagnosed during the most recent 5-year time-period of 2012-2017. On multivariable analysis for RS, Black patients with FL had a 32% higher excess mortality rate compared to White patients [adjusted excess hazard ratio (aEHR), 1.32; 95% CI, 1.15-1.51; p< .001], corresponding to a difference of 55 (95% CI, 24-86) excess deaths per 10000 person-years. For MZL, Black patients had a 40% higher excess mortality rate compared to White patients (aEHR 1.40; 95% CI, 1.18-1.66; p< .001), corresponding to a difference of 62 (95% CI, 26-98) excess deaths per 10000 person-years. No significant racial differences were detected for patients with WM. The greatest disparity was seen for younger Black patients with FL. Our findings highlight the need for interventions to improve the outcomes of Black patients with iNHLs, particularly younger Black patients with FL.