colon cancer symptom : What Are Polyps?

Polyps are growths which develop in the colon and other parts of the body as well. They vary in size and appearance. They may look like a wart when small and when they grow they may appear like a cherry on a stem or fig. They are important because they can with time turn into cancer. Sometimes they can bleed causing anemia. A polyp is defined as a growth that projects, often on a stalk, from the lining of the intestine or rectum. Polyps of the colon and rectum are almost always benign and usually produce no symptoms. They may, however, cause painless rectal bleeding or bleeding not apparent to the naked eye.

There may be single or multiple polyps. The incidence of polyps increases with age. The cumulative risk of cancer developing in an unremoved polyp is 2.5% at 5 years, 8% at 10 years, and 24% at 20 years after the diagnosis. The probability of any singular polyp becoming cancerous is dependent on its gross appearance, histologic features, and size. The relative risk of developing colon cancer after polyps have been removed is 2.3 compared to a relative risk of 8.0 for those who do not have the polyps removed. Polyps greater than 1 centimeter have a greater cancer risk associated with them than polyps under 1 centimeter.

Polyps with atypia or dysplasia are also more likely to progress on to colon cancer. The risk of cancer is much higher in sessile villous adenomas than in pedunculated tubular adenomas. Cancer is found in 40% of villous adenomas, as compared to 15% in tubular adenomas. The good news is that 65% of adenomas are tubular, with villous adenomas accounting for only 10% of adenomatous polyps. It has been shown that the removal of polyps by colonoscopy reduces the risk of getting colon cancer significantly.

Copyright© 10/13/96 by:
Donald E. Mansell, MD