What is Hereditary Colon Cancer?
It is estimated that 6% of all colorectal cancer occur in patients with inherited genetic abnormalities. The two most common of these are familial adenomatous polyposis (FAP), or a variant known as Gardner s Syndrome, and hereditary non-polyposis colon cancer (HNPCC). FAP comprises about 1% of all cases of colorectal cancer. This condition is inherited as an autosomal dominant genetic abnormality, meaning that about one-half of the kindred (off-spring) will develop the disease. In patients with FAP, polyps develop throughout the colon (average age of onset: 15-22) and if the colon is not removed cancer eventually develops (average age of onset: 39.) At the present time, if a patient is known to have FAP, their off-spring should be checked yearly with sigmoidoscopy beginning at age 12. Since polyps occur throughout the colon, examination of the rectum and lower colon by sigmoidoscopy is adequate screening. If adenomatous polyps develop, surgery is indicated to prevent the development of
