Even health conscious Americans report low rates of endoscopic screening for colorectal cancer

Sep 30 2004

A new study authored by American Cancer Society researchers finds even health conscious Americans report low rates of endoscopic screening for colorectal cancer.

The study found just over half (54 percent) of men and women reported having ever undergone endoscopy (sigmoidoscopy or colonoscopy). The percentage that underwent either procedure in the past five years for screening rather than for disease diagnosis or follow up was just 24 percent. The authors say the finding is remarkable considering the body of evidence showing endoscopy to be effective in reducing deaths from colorectal cancer, the third leading cause of cancer death in both men and women.

The findings, published in the October issue of the American Journal of Public Health, come from an analysis of data collected in 1997 from over 184,000 Americans aged 50 to 74 years. Respondents were participating in the Cancer Prevention Study (CPS) II Nutrition Cohort, and were generally more health-conscious than the U.S. population at large. Ann Chao, PhD, Michael Thun, MD, and their colleagues at the American Cancer Society examined the proportion of people who had undergone endoscopy (sigmoidoscopy or colonoscopy) and related this to the reasons for testing and demographic and lifestyle factors.

Overall, 58 percent of men and 51 percent of women in the study reported ever having undergone endoscopy, but only 35 percent reported being tested in the five years before 1997. Just 42 percent of men and 31 percent of women reported endoscopy for screening (rather than for disease diagnosis or follow-up), and only 29 percent of men and 21 percent of women reported having had endoscopy for screening in the five years before 1997.

Prevalence varied by demographic and lifestyle factors. Women, who are generally more likely to report preventive care measures, were less likely than men to report screening endoscopy. People aged 50-64 years and those lacking health insurance were also less likely to undergo the lifesaving tests. Some factors associated with increased risk of colorectal cancer, such as being overweight or obese, physically inactive, and a current smoker, were also associated with lower rates of screening. Meanwhile, the likelihood of screening endoscopy increased significantly with the reported number of first-degree relatives with colon cancer.

The authors conclude, “Efforts to increase colorectal cancer screening need to target women, all persons aged 50-64 years, and those with colorectal cancer risk factors. Future studies should distinguish endoscopy for screening from procedures for disease diagnosis and follow-up to avoid overestimating screening compliance.”

According to Dr. Thun, “These findings demonstrate that screening tests for colorectal cancer are underused, even in a health conscious population. This is remarkable since screening guidelines have been widely published and flexible sigmoidoscopy and colonoscopy have been proven to be effective in reducing colorectal cancer mortality. This is a clear example of how the burden of this cancer could be reduced just by applying what we already know.”