Colorectal Cancer – A malignant epithelial tumour arising from the colonic or rectal mucosa. It is the 3rd leading cause of cancer in the US. The risk of colorectal cancer (CRC) is reduced with a low-fat, high-fibre diet.
A malignant epithelial tumor arising from the colonic or rectal mucosa, which is the 3rd leading cause of cancer in ♂, 4th ? in ♀ in the US; risk of CC is ↓ with a low fat, high fiber diet Epidemiology 152,000 new cases, 57,000 deaths–1993, US Surveillance Annual Fecal occult blood testing is reported to ↓ mortality by 33% Predisposition Adenomatous polyps, family Hx–highest if 1st-degree family member–parents, siblings or children had CC and even higher if < age 55, ulcerative colitis Screening Most colorectal cancers develop from polyps; colon polypectomy ↓ CC; colon polyps and early cancer may be asymptomatic; screening is recommended every 3 yrs Clinical Rectal bleeding, occult blood in stools and, in advanced cases, bowel obstruction and weight loss Diagnosis Colonoscopy with biopsy, CT, barium enema Pathology Most CCs are adenocarcinomas; ‘raromas’ include lymphomas, neuroendocrine carcinomas, and sarcomas Molecular pathology CCs develop as genetic alterations accumulate–eg, K-ras oncogene on chromosome 12, and tumor-suppressor genes on chromosomes 5, 17p–which encodes p53, and 18q–DCC gene Management Surgery; cure likely if CA is confined to intestine.