[Interval colon cancer and possible causes].

Colorectal cancer that occurs during an interval between screening colonoscopies is called "interval carcinoma". These cancers are more frequent than would be expected, diagnosed in about tow per thousand patient years. There are three main causes for interval carcinomas: 50 % result from failed detection of polyps during colonoscopy, 25 % are tumors that develop during the screening interval and 25 % result from incomplete polypectomy. Knowing these etiologies screening makes it possible to optimize treatment. Colonoscopy of the highest quality is essential for providing reliable screening. Risk stratification during the first colonoscopy allows for optimal timing of follow-up-examinations. Difficult polypectomies require frequent follow-ups. Serrated adenomas should be treated like adenomas. Interval carcinomas are often detected during screening at an early stage: colonoscopy screening can save life of these patients.