Colorectal cancer screening

Colorectal cancer is a worldwide problem having global increases in the number of cases and deaths because of the expanding and aging of the population in both developing and developed countries. Screening methods are available which can reduce the incidence by removal of adenomas and can reduce deaths in diagnosed cancer cases by earlier stage detection. Faecal occult blood testing has the strongest proof of effectiveness based on randomised control trials; sigmoidoscopy has lesser proof based on case control studies, and barium enema the weakest proof of effectiveness. Screening colonoscopy has not been subjected to a randomised trial but there is now considerable evidence of its performance and safety and it has the ability to screen, diagnose, and treat (polypectomy) in one test and it is becoming increasingly offered. Many guidelines are now in place, all with positive a position on the effectiveness of screening. However, screening rates are low and many barriers are present that need to be overcome in order to make a major global impact on colorectal cancer incidence and mortality.