Colorectal Cancer Screening

The American Cancer Society estimates that over 107,000 people were newly diagnosed with colon cancer in 2002. More than 56,000 people died of this cancer that same year.2 Colorectal cancer develops in the rectum or the colon, and is one of the leading cancer killers in the US. Both men and women are at risk. Ninety-three percent of cases occur in people age 50 or older. The risk of developing colorectal cancer increases with age.

There are screening programs for colorectal cancer. The primary purpose of a screening test is to identify disease in people who don’t have symptoms yet. Catching the problem at an early stage may allow treatment to prevent the full-blown disease, or at least to reduce its severity. The occurrence of the disease and the mortality from the disease must justify the effort and the expense of screening.

In the case of colorectal cancer, these criteria have been met. The screening test looks for cancerous cells in the colon. The key question: is there evidence that colorectal cancer screening confers a survival benefit due to the early detection of colorectal cancer? In other words, what is the absolute risk reduction (ARR) for people who have had the screening test compared to people who have not?