Prognosis of Inherited Colon Cancer
Colon cancer is the third most commonly diagnosed cancer in the United States. Family history is a key risk factor; as many as 1 in 5 of those diagnosed have family members who are similarly afflicted, and in 5 to 10 percent of cases, patients have inherited specific genes that predispose them to the disease. If you know you've inherited one of these genes, however, you may be able to take preventive measures.
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Inherited Colon Cancer
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The cells in your body have built-in mechanisms to recognize and repair damaged DNA; the genes involved in these mechanisms are called DNA damage repair genes. If you inherit a mutated version of a DNA damage repair gene or a gene that regulates cell growth, cells in some of your organs are much more likely to become cancerous. Scientists have identified several specific genetic mutations inherited in families that can dramatically increase the risk of developing colon cancer--often at a much younger age. Familial adenomatous polyposis(FAP), hereditary nonpolyposis colorectal cancer(HNPCC), and Peutz-Jegher's syndrome(PJS) are three such heritable disorders.
Prognosis
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People with HNPCC have a roughly 80 percent chance of developing colon cancer, typically before the age of 50. Virtually all patients with FAP develop colon cancer by the time they turn 40. People with PJS have fifteen-fold higher risk of colon cancer compared with members of the general population. These inherited mutations may also predispose patients to developing benign or cancerous growths in other organs as well.
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Prospects for Treatment
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With colorectal cancer as with other cancers, the sooner it's diagnosed and treated the better your chances--in other words, prognosis improves with earlier diagnosis. Cancers that remain confined to the bowel mucosa are highly treatable; if cancer has spread through the bowel wall to the lymph nodes, however, it becomes much more difficult to treat successfully. Patients with hereditary colon cancer, however, are at a high risk for recurrence. If you know you've PJS, it's important to be checked regularly to ensure that any polyps or other abnormalities are detected and treated as quickly as possible. With certain inherited mutations like FAP and HNPCC, however, other more drastic preventative measures may be necessary.
Prevention & Prognosis
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In patients with FAP, hundreds or even thousands of polyps form in the intestines, making it impossible to remove each surgically. With HNPCC, on the other hand, the risk of recurrence following treatment for cancer is extremely high. With both HNPCC and FAP, then, doctors will typically perform surgery to remove the entire colon. In some patients with HNPCC, it may be advisable to remove the colon as a preventative measure since patients with HNPCC have such a high risk of developing colon cancer.
Considerations
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Mutations like those responsible for FAP and PJS can predispose patients to other common cancers like cancer of the stomach or ovarian cancer. It's essential to undergo regular screening to catch cancer as quickly as possible if it develops. For brothers, sisters or children of people with FAP, it's recommended that you begin colon checks at 12 years of age; people with HNPCC are advised to start undergoing colonoscopies at age 21 or sooner if members of their families have been diagnosed with cancer at a young age.
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