African Americans get more colorectal cancer than whites and die more often.
Whether this is because of different biology or lack of access to high-quality medical care has long been debated.
In a new study, blacks had very similar rates of polyps found during a screening flexible sigmoidoscopy. But they were less likely to get a recommended follow-up colonoscopy.
While about 1 in 4 people had polyps discovered during their sigmoidoscopy, nearly identical percentages for blacks and whites, blacks got colonoscopy follow-up about 12 percent less often than whites.
For those who did get a colonoscopy, adenomas and advanced adenomas were just as likely in whites and blacks, as was the rate of cancers discovered.
The Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial screened 60,572 people for colorectal cancer using flexible sigmoidoscopy. Doctors recommended those who had abnormalities discovered during the screening test have a colonoscopy. However, the trial did not pay for the follow-up exam.
Analysis of the PLCO trial found,
- 23.9 percent of whites had abnormalities found during flexible sigmoidoscopy compared to 25.5 percent of blacks, which was an insignificant difference.
- 72.4 percent of whites got a diagnostic colonoscopy compared to 62.6 percent of blacks
- During colonoscopy, 23.1 percent of blacks and 22.5 percent of whites had an advanced adenoma found.
- Nearly identical percentages had cancer discovered (2.1 percent of blacks and 1.5 percent of whites).
- Advanced adenomas were more frequently found on the right side of the colon in blacks (8.5 percent) than in whites (5.5 percent) suggesting that full colonoscopy that reaches the right side of the colon may be particularly important in screening African Americans.
Lead author Adeyinka O. Laiyemo, MD, MPH, from Howard University School of Medicine, and colleagues concluded,
We observed a lower follow-up for screen-detected abnormalities among blacks when compared with whites but little difference in the yield of colorectal neoplasia. Health-care utilization may be playing more of a role in colorectal cancer racial disparity than biology.
The study did not look at reasons that African Americans were less likely to get follow-up colonoscopies. However, in an editorial accompanying the study results in the Journal of the National Cancer Institute, John Z. Ayanian, MD, MPP, from the Department of Health Care Policy discussed some potential barriers to follow-up care.
He pointed out that other research has shown:
- Blacks are less likely to have a primary care physician.
- They live more often in low-income communities with limited access to gastroenterologists.
- They may lack insurance that covers colonoscopy.
- They may not be able to afford out-of-pocket costs for colonoscopy not covered by insurance.
The barriers concerned Dr. Ayanian, who wrote,
These gaps in follow-up care were particularly concerning because up to one-quarter of participants who did not undergo colonoscopy were likely to have advanced adenomas that were neither detected nor removed. Valuable opportunities to prevent colorectal cancer were thus lost in these patients.
He called for programs like that in New York City which increased colonoscopy screening rates for black adults from 35 percent to 64 percent in four years to be expanded to other communities. The program in New York uses public education, improved tracking systems, and patient navigators to get low-income people to screening. He also cited the expanded Centers for Disease Control and Prevention program that will promote colorectal cancer screening for low-income Americans in 22 states and four tribal organizations.
Colorectal cancer is one important disease in which racial and socioeconomic disparities in outcomes can most readily be eliminated by ensuring that all eligible adults are effectively screened and abnormal findings are fully treated.