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Elderly black patients more likely to develop colorectal cancer

The risk for interval colorectal cancer was 31% greater in elderly black patients enrolled in Medicare than in white patients, with a more noticeable difference seen in cancer of the distal colon and rectum and when examined by physicians with higher polyp detection rate, according to recent data.

“Patterns of risk for interval [colorectal cancer (CRC)] by race/ethnicity are not well-known,” Stacey A. Fedewa, PhD, MPH, from Surveillance and Health Services Research at the American Cancer Society, and colleagues wrote in Annals of Internal Medicine. “Disparities between black and white persons in risk for interval CRC are of particular concern because black persons have the highest incidence of and mortality rates from CRC of any race or ethnic group in the United States, with incidence rates 22% to 27% higher than in white persons.”

Researchers performed a population-based cohort study of patients aged 66 to 75 years enrolled in a Medicare program who received a colonoscopy between 2002 and 2011 to determine if the risk for interval CRC among patients differed by race/ethnicity and if this difference was dependent on variances in the quality of colonoscopy, based on previous research that showed a poorer quality of mammogram performed in black patients than white patients. Quality of colonoscopy was measured by physician’s polyp detection rate (PDR) which was calculated by dividing the number of patients who received polypectomy by the total number of colonoscopies performed over the course of a 5-year period. They used Kaplan-Meier curves and adjusted Cox models to assess cumulative probabilities and HRs of interval CRC, defined as a CRC diagnosis 6 to 59 months after colonoscopy.

There were 2,735 cases of interval colorectal cancer identified. The researchers found that 52.8% of black patients and 46.2% of white patients received colonoscopy from physicians with a lower PDR. By the end of follow-up, the probability of interval CRC was 7.1% in black patients and 5.8% in white patients. Black participants had significantly higher risk for interval CRC compared with whites (HR = 1.31; 95% CI, 1.13-1.51). Racial/ethnic disparities were more pronounced for distal colon (HR = 1.45; 95% CI, 1-2.11) and rectal cancer (HR = 1.7; 95% CI, 1.25-2.3) than for proximal colon cancer (HR = 1.17; 95% CI, 0.96-1.42). Differences between black and white patients were greater among physicians with higher PDRs; however, adjustment for PDR did not alter HRs by race/ethnicity.

“In this population-based study of elderly Medicare enrollees, risk for interval CRC was 31% higher among black persons than white persons,” Fedewa and colleagues wrote. “Future studies examining this issue are warranted, given the higher overall risk for interval CRC in black populations as well as the larger disease burden in the group.” – by Savannah Demko

Disclosures: The researchers report no relevant financial disclosures.