Health care utilization, not biology, may affect colorectal cancer disparities

Blacks and whites were equally likely to need a follow-up colonoscopy after a screening flexible sigmoidoscopy, but blacks were less likely to receive follow-up, suggesting that disparities seen in colorectal cancer may be due to differences in health care utilization.

U.S. researchers examined data from 57,561 whites and 3,011 blacks enrolled in the ongoing Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. Patients underwent a screening flexible sigmoidoscopy. If polyps or lesions were detected, the patients were referred to their personal physician for a follow-up colonoscopy, the cost of which was not covered by the study.

Overall, 23.9% of whites and 25.5% of blacks had abnormal exams. Within one year after the abnormal screening, 72.4% of whites and 62.6% of blacks had a follow-up diagnostic colonoscopy.

In multivariate analysis, blacks were less likely to undergo diagnostic evaluation compared with whites (risk ratio=0.88; 95% CI, 0.83-0.93). There were no significant differences for prevalence of adenoma, advanced adenoma or advanced pathology, according to the researchers.

According to the researchers, the findings suggested that “the biology of colorectal cancer may not be materially different by race, at least in the early stages of carcinogenesis, but instead that health care utilization differences among the races may play a more important role in the observed disparities in colorectal cancer.

“Targeted interventions aimed at increasing the uptake of screening among minority populations and provision of an adequate diagnostic component for screening programs is essential if colorectal cancer disparities were to be eliminated,” they wrote.

Laiyemo AO. J Natl Cancer Inst. 2010;doi:10.1093/jnci/djq068.