The May of 2012 issue of the New England Journal of Medicine reports that sigmoidoscopy rather than colonoscopy could be used to screen for colon cancer. A clinical trial of 150,000 people was done where half had sigmoidoscopy and the other have nothing. They were followed over 12 years and over that interval there were 89 fewer cancer deaths and 275 more colon cancers found in the group getting the sigmoidoscopy. These numbers can be translated to show that 749 of 750 sigmoidoscopies would be unnecessarily done to save one death and that 499 of 500 sigmoidoscopies would needlessly be done to find one cancer. This sound a lot different than when one looks at percentages rather than real numbers.
When using percentages, it can be stated that people would be 21% less likely to develop cancer and 26% less likely to die if a sigmoidoscopy were done to screen for colon cancer. The US Preventive Services Task Force agrees that sigmoidoscopy is a reasonable alternative for colonoscopy because it works nearly as well as a colonoscopy, is far less expensive, safer, and much less invasive.
