The American Cancer Society has published new colon cancer screening guidelines, based on new epidemiologic data that show a dramatic increase in incidence of colorectal cancer in people under age 50. Click here for the article in which the new guidelines are published. The authors make a compelling argument that the biology of colorectal cancer is changing for unknown reasons. In contradistinction, the incidence of colon cancer in people over the age of 50 is decreasing. The authors postulate that increased compliance with screening may play a role. Well performed randomized trials unequivocally show that screening will lower incidence and mortality (by finding polyps before they can become cancerous). What is changing is the prevalence of screening. Part of that increase in screening is physician advocacy and part is patient compliance. The marketing of tests such as Cologuard (testing for DNA mutations suggestive of cancer in the stool) may be making an impact as well.
Dr. Stark weighs in: why younger people are getting more colon cancer is up for discussion. Increasing obesity rates are likely playing a role. The American Cancer Society has taken the lead in recommending screening starting at age 45 instead of the usual 50. The authors point out that certain ethnic groups such as native Alaskans have a markedly increased incidence; nonetheless no group has been spared the changing demographic. The issue of which test to take is unsolved. Whether the Cologuard test can substitute for a colonoscopy is really an unanswered question. The significance of a negative Cologuard needs to be nailed down. If it turns out that a negative Cologuard obviates the need for colonoscopy that would be a wonderful step in improving compliance, but we don’t know that yet.