Impact of Race and Age and their Interaction on Survival Outcomes in Patients With Diffuse Large B-Cell Lymphoma.

Background: Advances in treatment for patients with Diffuse Large B-Cell Lymphoma (DLBCL) have led to improved patient outcomes but the magnitude of these disparities remains understudied with regards to improved survival outcomes. We sought to describe changes in DLBCL survival trends over time and explore potential differential survival patterns by patients' race/ethnicity and age.

Methods: We utilized the Surveillance, Epidemiology, and End Results (SEER) database to identify patients diagnosed with DLBCL from 1980 to 009 and determined 5-year survival outcomes for all patients, categorizing patients by year of diagnosis. We used descriptive statistics and logistic regression, adjusting for stage and year of diagnosis, to describe changes in 5-year survival rates over time by race/ethnicity and age.

Results: We identified 43,564 patients with DLBCL eligible for this study. Median age was 67 years (ages: 18-64 = 44.2%, 65-79 = 37.1%, 80 + = 18.7%). Most patients were male (53.4%) and had advanced stage III/IV disease (40.0%). Most patients were White race (81.4%), followed by Asian/Pacific Islander (API) (6.3%), Black (6.3%), Hispanic (5.4%), and American Indian/Alaska Native (AIAN) (0.05%). Overall, the 5-year survival rate improved from 35.1% in 1980 to 52.4% in 2009 across all races and age groups (odds ratio [OR] for 5-year survival with increasing year of diagnosis = 1.05, P < .001). Patients in racial/ethnic minority groups (API: OR = 0.86, P < .0001; Black: OR = 0.57, P < .0001; AIAN: OR = 0.51, P = .008; Hispanic: 0.76, P = 0.291) and older adults (ages 65-79: OR = 0.43, P < .0001; ages 80+: OR = 0.13, P < .0001) had lower 5-year survival rates after adjusting for race, age, stage, and diagnosis year. We found consistent improvement in the odds of 5-year survival for year of diagnosis across all race and ethnicity groups (White: OR = 1.05, P < .001; API: OR = 1.04, P < .001; Black: OR = 1.06, p<.001; AIAN: OR = 1.05, P < .001; Hispanic: OR = 1.05, P < .005) and age groups (ages 18-64: OR = 1.06, P < .001; ages 65-79: OR = 1.04, P < .001; ages 80+: OR = 1.04, P < .001).

Conclusion: Patients with DLBCL experienced improvements in 5-year survival rates from 1980 to 2009, despite persistently lower survival among patients in racial/ethnic minority groups and older adults.