Ethnic variations in diagnosis, treatment, socioeconomic status, and survival in a large population-based cohort of elderly patients with non-Hodgkin lymphoma

BACKGROUND. There is a lack of research on ethnic disparities in survival among patients with non-Hodgkin lymphoma (NHL), although these disparities have been documented for patients with many other tumors. METHODS. A retrospective cohort of 13,321 patients diagnosed with incident NHL at age ≥65 years from 1992 to 1999 were identified from the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database with 11 years of follow- up. Of these patients, 11,868 were Caucasians, 533 were African Americans, and 920 were other ethnicities. A time-to-event Cox regression model was used to examine the relative risk of all-cause and disease-specific mortality. RESULTS. A larger proportion (72.2%) of African Americans were in the poorest quartile of socioeconomic status as measured by the poverty level compared with 21.8% of Caucasians, and 43.2% of African Americans received chemotherapy compared with 52.4% of Caucasians (P <.01). Hazard ratio of all-cause and NHL-specific mortality increased significantly with age, advanced stage, higher comorbidity scores, and poorer socioeconomic status. Patients receiving either chemotherapy or radiotherapy or both were significantly less likely to die. After taking into account differences in treatment, comorbidity, and socioeconomic status, there was no statistically significant difference in the risk of all-cause (hazard ratio, 0.97; 95% confidence interval, 0.88-1.08) and disease-specific mortality (hazard ratio, 1.07; 95% confidence interval, 0.92-1.25) between African Americans and Caucasians. CONCLUSIONS. The risk of mortality in patients with NHL was associated with socioeconomic status and was reduced in patients receiving chemotherapy. No significant differences in the risk of mortality were observed between African Americans and Caucasians after controlling for factors such as treatment and socioeconomic status.