Race and Colon Cancer Survival in an Equal-Access Health Care System

Abstract

Studies have shown that Whites have a higher colorectal cancer survival rate than Blacks. However, it is unclear whether racial disparities result from unequal access to medical care or factors other than health care access or both. This study assessed whether non-Hispanic Whites (NHW) and non-Hispanic Blacks (NHB) differ in colon cancer survival in an equal-access health care system and examined whether racial differences varied by demographic and tumor characteristics. The study included 2,537 Military Health System patients diagnosed with colon cancer between 1998 and 2007. Median follow-up time was 31.4 months. Cox models estimated HRs and 95% confidence intervals (CI) for race, overall and stratified by age at diagnosis, sex, and tumor stage. No difference in overall survival (OS) between NHWs and NHBs was observed in general. However, among patients younger than 50 years old, NHBs experienced significantly worse OS than NHWs (HR: 2.03, 95% CI: 1.30-3.19). Furthermore, stratification by sex and tumor stage showed that this racial disparity was confined to women (HR: 2.87; 95% CI: 1.35-6.11) and patients with distant stage disease (HR: 2.45; 95% CI: 1.15-5.22) in this age group. When medical care is equally available to NHWs and NHBs, similar overall colon cancer survival was observed; however, evidence of racial differences in survival was apparent for patients younger than 50 years old. This study suggests that factors other than access to care may be related to racial disparities in colon cancer survival among younger, but not older, patients.