In recent years we have gained increasing insight into the development of colorectal cancers. Polyps play a significant role in the development of cancer and are recognized as the highest risk identifiable precursor of cancer. The Role of Polyps and the Polyp to Cancer Sequence Polyps are abnormal growths arising from the lining of the colon or rectum and protruding into the intestinal canal or lumen. Polyps, which continue to accumulate new cells and to grow are said to be neoplastic . Most of these growths are benign, but neoplastic conditions that continue to grow into polyps can develop into colorectal cancer.
Polyps develop as the surface cells of the lining of the colon build up.
Both mechanisms may also act together. As polyps grow they assume a greater risk of becoming malignant. The chance of a very small polyp being cancerous is less than one in five hundred, while the chance for a larger polyp, about one centimeter, is about one in ten. The chance that a large polyp, over two centimeters, is cancerous may be as high as one in two. Although we are not sure what causes polyp growth, researchers believe that the same genetic and lifestyle factors that cause colorectal cancer are involved.