Racial and ethnic disparities in cancer survival by neighborhood socioeconomic status in Surveillance, Epidemiology, and End Results (SEER) Registries.

INTRODUCTION

Reducing cancer disparities is a major public health objective. Disparities often are discussed in terms of either race and ethnicity or socioeconomic status (SES), without examining interactions between these variables.

METHODS

Surveillance, Epidemiology, and End Results (SEER)-18 data, excluding Alaska Native and Louisiana registries, from 2002 to 2008, were used to estimate five-year, cause-specific survival by race/ethnicity and census tract SES. Differences in survival between groups were used to assess absolute disparities. Hazard ratios were examined as a measure of relative disparity. Interactions between race/ethnicity and neighborhood SES were evaluated using proportional hazard models.

RESULTS

Survival increased with higher SES for all racial/ethnic groups and generally was higher among non-Hispanic white and Asian/Pacific Islander (API) than non-Hispanic black and Hispanic cases. Absolute disparity in breast cancer survival among non-Hispanic black vs non-Hispanic white cases was slightly larger in low-SES areas than in high-SES areas (7.1% and 6.8%, respectively). In contrast, after adjusting for stage, age, and treatment, risk of mortality among non-Hispanic black cases compared with non-Hispanic white cases was 21% higher in low-SES areas and 64% higher in high-SES areas. Similarly, patterns of absolute and relative disparity compared with non-Hispanic whites differed by SES for Hispanic breast cancer, non-Hispanic black colorectal cancer, and prostate cancer cases. Statistically significant interactions existed between race/ethnicity and SES for colorectal and female breast cancers.

DISCUSSION

In health disparities research, both relative and absolute measures provide context. A better understanding of the interactions between race/ethnicity and SES may be useful in directing screening and treatment resources toward at-risk populations.