Screening and Polyp Removal Spur Decline.

• Position: Brief Article

A steady decline in the incidence of colorectal cancer since 1986 is most likely due to early screening and removal of precancerous polyps, researchers from the University of Illinois at Chicago conclude. Changes in diet and lifestyle, including exercise, have had only a subsidiary role, they maintain. After rising for 13 years in the U.S., incidence of colorectal cancer suddenly reversed in 1986 and has declined since then at a rate greater than one percent per year. Nevertheless, it remains the nation's second most deadly cancer, striking nearly 130,000 Americans and taking some 56,000 lives each year.

The researchers, led by Richard L. Nelson, matched data on incidence of colorectal cancer with exposure to various suspected risk variables, such as dietary fat, energy intake, serum cholesterol, physical activity, overweight, alcoholic beverages, dietary fiber, specific nutrients, estrogen supplementation, aspirin, cigarettes, and gallbladder removal. They found the strongest correlation between the incidence decline and the sharp increase in screening by colonoscopy, a thorough examination of the full lining of the colon using a long, flexible, tubular device called a colonoscope. During colonoscopy, the surgeon sees the inside of the colon...