Racial Disparities in Diffuse Large B Cell Lymphoma: A VA Population Study.

Background: Racial disparities in diffuse large B cell non-Hodgkin’s lymphoma (DLBCL) are not well studied. Racial differences in outcome are not well recognized given majority of patients with DLBCL are white. The VA health care system offers a platform to study those racial differences given similar other variables and socioeconomic status among those patients.

Methods: This was a retrospective analysis. The VA Central Cancer Registry (VACCR) database was used to identify patients with DLBCL diagnosed between 1995 and 2005. There are approximately 120 VA medical centers diagnosing and/or treating patients with cancer. The VACCR aggregates the data collected by the medical centers’ cancer registries. Data were extrapolated and analyzed using bio-statistical software SPSS. Variables included age, sex, stage of disease, histology subtype, date of diagnosis, date of last contact, date of relapse, vital status, family history of cancer, tobacco history, alcohol history, Agent orange exposure and whether patients received chemotherapy and or radiation. Independent t test was used for comparing continuous variables and chi square test for categorical variables. Wilcoxon test was used to compare survival among the two groups.

Results: There were 2792 patients with DLBCL at the VA system, 2402 white and 323 black patients. Sixty-seven patients from other racial groups were excluded from this analysis. The mean age of presentation among blacks was 57.8 years compared to 65.7 years among whites (P-value < 0.005). More Black patients had history of alcohol use, and smoking. More white patients had family history of cancer. No differences in histology subtypes were observed. Other baseline characteristics were similar. No difference in stage of disease was noted at presentation. IPI score data were not available. Similar proportion of patients received multi-agent chemotherapy among the two groups, 70 % for blacks and 67% for whites (P-value 0.58). Among blacks 16 % of patients received radiation while 19.5 % white patients did (P-value 0.73). The 5-year overall survival for blacks was 24 % compared to 29% for whites (P-value 0.92, Wilcoxon test). No statistically significant differences in survival were noted between the two races within each clinical stage. Using Cox regression multivariable analysis age, stage and chemotherapy were the only statistically significant independent variables affecting survival.

Conclusions: DLBCL is less common among blacks. Blacks diagnosed with DLBCL are more likely to present at younger age. The treatment and outcome of DLBCL among blacks are not different from whites within the VA system.