[International status colorectal cancer screening and quality assurance of screening-colonoscopy].

Bowel cancer is frequent, early stages have much better prognosis and drug treatment of late stages is increasingly very expensive. Screening for colorectal cancer has the potential for both early detection and prevention. For a screening intervention colonoscopy is very invasive and holds the small risk of serious complications. Colonoscopy plays a key role for further diagnosis and intervention in all programs. Current international screening activities are presented. The emerging evidence on effectiveness of screening suggests that all strategies may have similar effect sizes. Participation rates and quality assurance thus are of key importance for realizing potential net health gains. Participation rates are higher for stool tests than for sigmoidoscopy and colonoscopy. For quality assurance of screening-colonoscopy an established range of quality measures is available. The possibility of systematic quality assurance also in the context of opportunistic screening like in Austria is proven by Germany and Poland.