Improvements in Survival After Follicular Lymphoma by Race/Ethnicity and Socioeconomic Status: A Population-Based Study

Abstract

A recent report suggested improvements in survival after follicular lymphoma (FL), but not for all racial/ethnic groups. To better understand the reasons for these FL survival differences, we examined the joint influences of diagnostic period, race/ethnicity, and neighborhood socioeconomic status (SES) on survival in a large population-based case series. All patients (n = 15,937) diagnosed with FL between 1988 and 2005 in California were observed for vital status through November 2007. Overall and FL-specific survival were analyzed with Kaplan-Meier and Cox proportional hazards regression. Neighborhood SES was assigned from United States Census data using residence at diagnosis. Overall and FL-specific survival improved 22% and 37%, respectively, from 1988 to 1997 to 1998 to 2005, and were observed in all racial/ethnic groups. Asian/Pacific Islanders had better survival than non-Hispanic white, Hispanic, and black patients who had similar outcomes. Lower neighborhood SES was associated with worse survival in patients across all stages of disease (P for trend < .01). Patients with the lowest SES quintile had a 49% increased risk of death from all causes (hazard ratio [HR] = 1.49, 95% CI, 1.30 to 1.72) and 31% increased risk of death from FL (HR = 1.31; 95% CI, 1.06 to 1.60) than patients with the highest SES. Evolving therapies have likely led to improvements in survival after FL. Although improvements have occurred within all racial/ethnic groups, lower neighborhood SES was significantly associated with substantially poorer survival.