Researchers from the United States Department of Veteran Affairs investigated the benefits of using the most comprehensive type of screening for colorectal cancer in people without any symptoms. They studied over 3,000 healthy people between 50 and 75. Ten percent were found to have colon cancer or serious precancerous growths.
Most colorectal cancers begin with polyps that, unless removed, can become cancerous over time.
Sigmoidoscopy, a less expensive and time-consuming procedure, is generally recommended for those over the age of 50 with an average risk for colorectal cancer. This is the largest study to screen the entire colon for cancer in people without symptoms. It is also the first study to compare these two types of exams. The results need to be verified in women, since 97 percent of study participants were men. Colonoscopy can identify a number of pre-cancerous polyps that sigmoidoscopy can miss.