Colon cancer screening update and management of the malignant polyp.

Colorectal carcinoma is common, but screening for this cancer has found less acceptance with the public than screening for breast, prostate, and cervical cancer. Available methods include fecal occult blood tests (FOBTs), flexible sigmoidoscopy (FOS), double-contrast barium enema, colonoscopy, computed tomographic colography, and fecal DNA. Evaluation of these options demonstrates that colonoscopy at ages 55 and 65 offers the best combination of reduction in colorectal cancer at the lowest cost. However, when compliance with screening recommendations is very high, costs are high, and the proportion of cancers arising from adenomas is low, the combination of FOS and FOBT is most cost effective. Malignant polyps look friable and irregular and feel hard. Sessile malignant polyps need to be treated by formal resection. Patients with pedunculated polyps with favorable histology (clear margin, well or moderately differentiated, no lymphovascular invasion) can be observed, and those whose polyps show unfavorable histology should have the polyp-bearing segment of colon resected along with its draining lymph nodes.