Benefits and Risks of Colorectal Cancer Screening

sary diagnostic and therapeutic steps of all examination modalities, the indications for general CRC screening, risk situations, as well as the necessary follow-up intervals after diagnosis and resection [4]. In most cases, CRC develops via precursor lesions, socalled polyps or adenomas, the progression of which through accumulation of genetic changes is well known (adenomacancer sequence). An important fact is that these tumors grow slowly over 10–15 years, and because of this time frame and due to the process of growth into the lumen of the gut, they can be easily detected via fecal analysis (occult blood test) or by endoscopy (colonoscopy) with the possibility of immediate resection of precursor lesions or early cancers. Recent investigations have demonstrated that especially in the right-sided colon there are subgroups of polyps, so-called serrated adenomas, which grow faster [5]. Since 2002 in Germany, an enhanced but still opportunistic prevention and early detection program exists for both sexes, which includes the guaiac-based fecal occult blood test (gFOBT) beginning with the 50th year of age as well as screening colonoscopy beginning with the 55th year of age. The stool test is offered annually up to the 55th year, and in the case of refusal of colonoscopy every 2 years beginning with the 56th year. Screening colonoscopy can be repeated 10 years after an inconspicuous initial colonoscopy. The basis for the implementation and validation of the gFOBT was formed by a number of large randomized studies with a long-term follow-up and the highest evidence level of 1A. According to these studies, it is accepted that with annual or biennial use of the test a significant reduction in CRC incidence of approximately 20% can be achieved [6–8]. Colorectal Cancer Screening: Pro Jurgen F. Riemann (Ludwigshafen)