Racial differences in tumor stage and survival for colorectal cancer in an insured population

Authors


  • This research was made possible by the cooperation of the participating Cancer Research Network members. We are particularly grateful to Donald J. Bachman, MS; Jennifer Ellis, MSPH; Hassan Fouayzi, MS; Rick Krajenta; Liyan Liu, MSPH; Janis Yao, MS; and Fagen Xie, PhD, whose collective work in building the Cancer Research Network's Virtual Data Warehouse made this research project possible.

Abstract

BACKGROUND.

Despite declining death rates from colorectal cancer (CRC), racial disparities have continued to increase. In this study, the authors examined disparities in a racially diverse group of insured patients.

METHODS.

This study was conducted among patients who were diagnosed with CRC from 1993 to 1998, when they were enrolled in integrated healthcare systems. Patients were identified from tumor registries and were linked to information in administrative databases. The sample was restricted to non-Hispanic whites (n = 10,585), non-Hispanic blacks (n = 1479), Hispanics (n = 985), and Asians/Pacific Islanders (n = 909). Differences in tumor stage and survival were analyzed by using polytomous and Cox regression models, respectively.

RESULTS.

In multivariable regression analyses, blacks were more likely than whites to have distant or unstaged tumors. In Cox models that were adjusted for nonmutable factors, blacks had a higher risk of death from CRC (hazard ratio [HR], 1.17; 95% confidence interval [95% CI], 1.06–1.30). Hispanics had a risk of death similar to whites (HR, 1.04; 95% CI, 0.92–1.18), whereas Asians/Pacific Islanders had a lower risk of death from CRC (HR, 0.89; 95% CI, 0.78–1.02). Adjustment for tumor stage decreased the HR to 1.11 for blacks, and the addition of receipt of surgical therapy to the model decreased the HR further to 1.06. The HR among Hispanics and Asians/Pacific Islanders was stable to adjustment for tumor stage and surgical therapy.

CONCLUSIONS.

The relation between race and survival from CRC was complex and appeared to be related to differences in tumor stage and therapy received, even in insured populations. Targeted interventions to improve the use of effective screening and treatment among vulnerable populations may be needed to eliminate disparities in CRC. Cancer 2007;109:612–620. © 2006 American Cancer Society.

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