Medical Advances and Racial/Ethnic Disparities in Cancer Survival

Abstract

Background: Although advances in early detection and treatment of cancer improve overall population survival, these advances may not benefit all population groups equally and may heighten racial/ethnic differences in survival.

Methods: We identified cancer cases in the Surveillance, Epidemiology and End Results program, who were ages ≥20 years and diagnosed with one invasive cancer in 1995 to 1999 (n = 580,225). We used 5-year relative survival rates to measure the degree to which mortality from each cancer is amenable to medical interventions (amenability index). We used Kaplan-Meier methods and Cox proportional hazards regression to estimate survival differences between each racial/ethnic minority group relative to Whites, by the overall amenability index, and three levels of amenability (nonamenable, partly amenable, and mostly amenable cancers, corresponding to cancers with 5-year relative survival rate <40%, 40-69%, and ≥70%, respectively), adjusting for gender, age, disease stage, and county-level poverty concentration.

Results: As amenability increased, racial/ethnic differences in cancer survival increased for African Americans, American Indians/Native Alaskans, and Hispanics relative to Whites. For example, the hazard ratios (95% confidence intervals) for African Americans versus Whites from nonamenable, partly amenable, and mostly amenable cancers were 1.05 (1.03-1.07), 1.38 (1.34-1.41), and 1.41 (1.37-1.46), respectively. Asians/Pacific Islanders had similar or longer survival relative to Whites across amenability levels; however, several subgroups experienced increasingly poorer survival with increasing amenability.

Conclusions: Cancer survival disparities for most racial/ethnic minority populations widen as cancers become more amenable to medical interventions. Efforts in developing cancer control measures must be coupled with specific strategies for reducing the expected disparities. (Cancer Epidemiol Biomarkers Prev 2009;18(10):2701–8)