The American Cancer Society recommends that colon cancer screening should start at age 50, but this may be too late. Since the mid-1990s, experts have noticed a rising trend in colon and rectal cancer incidence and mortality among men and women under 55 in the United States. One study found that 30 percent of newly diagnosed people are younger than 55.

Based on an analysis of more than 6,000 colonoscopies, French researchers recently reported that the detection of precancerous growths jumped by 400 percent from the 40-to-44 age group to the 45-to-49 group. The average number of polyps in the colon and the proportion of people with adenomas (benign tumors) rose much more sharply from the 40-to-44 group to the 45-to-49 group than they did from the 45-to-49 group to the 50-to-54 group.

“The results of our research strongly indicate that screening for colorectal cancer should begin at the age of 45,” said researcher David Karsenti, MD, of the French Society of Digestive Endoscopy.