Cáncer de colon y recto

Abstract

Colorectal cancer (CRC) is today the most frequent type of cancer, with a higher incidence in men. 90% of cases are diagnosed over the fifth decade of life. Positive familial history (familial CRC, Lynch syndrome or familial adenomatous polyposis [FAP]) as well as personal previous CRC, colonic adenomas or colonic inflammatory bowel disease (IBD) represent the main risk factors for CRC. Adenoma-adenocarcinoma sequence, along with APC gene mutations, is the best known colorectal carcinogenetic pathway, although there are other pathways implicated namely DNA mismatch repairing genes mutations, in Lynch syndrome, or hypermetilation epigenetic phenomenons characteristic of serrated lesions. Clinical symptoms depend on anatomic localization of CRC, being rectal bleeding the most frequent one. Colonoscopy is considered the gold standard for colorectal pathology and has a higher performance than virtual colonoscopy or double contrast barium enema. Screening programs allow early CRC detection but also removal of premalignant colonic lesions such as adenomas, decreasing CRC incidence. Biennial fecal occult blood test (FOBT) or colonoscopy every ten years are the most accepted screening methods although there are others.