Risk Factors
for Colorectal Cancer
Scientists and doctors have identified several risk factors for developing colorectal cancer. Having one or more of these risks does not necessarily mean you will get the cancer; an absence of risk factors does not ensure against it. Some risk factors, primarily polyps and lifestyle, can be controlled while risks like age and family history cannot.
Know your risk for colorectal cancer and set up an appropriate screening plan with your gastroenterologist
or family practitioner. |
Age: About 90% of those who develop colorectal cancer are over fifty. Risk starts to rise after forty, increasing sharply from age fifty on. If you’re fifty, get screened, if you haven’t already.
Family History / Heredity: Any relatives who’ve had colorectal cancer? Your risk is significantly higher, especially if your family member had it before age sixty.
If you are in this higher risk group, start screening before fifty. Depending on your specific risks such as number of relatives, their age at diagnosis, how closely related, etc., you may need screening as early as thirty-five. See below - Other Genetic - for more about heredity and genetics.
Polyps: Polyps are small growths that often develop along the walls of the colon and rectum. Though most are benign (non-cancerous), most colorectal cancer develops from these initially benign polyps. During colonoscopy, polyps are removed to prevent them from growing and becoming cancerous.
If your doctor finds any polyps when you are screened, you’ll need more frequent colonoscopies to check for regrowth or new polyps. And as with a family history of colon cancer, if any of your close relatives have had polyps, you should start screening before age 50.
Lifestyle: Smoking; lack of exercise; obesity; a diet rich in meat, especially processed meat; drinking more than two drinks daily, particularly distilled spirits; as well as high fat, low fiber diets, have all been implicated in increasing colorectal cancer risk.
There are contradictory study results for most lifestyle factors. But, since spouses of people with colon cancer are also more likely to develop the disease, lifestyle factors clearly do contribute.
See page 5 for ways to Decrease Your Colorectal Cancer Risk.
Inflammatory Bowel Disease: Inflammatory bowel disease (IBD) affects millions. Common forms of IBD are ulcerative colitis and Crohn’s colitis, both chronic inflammations of the colon. If you have IBD, you are more likely to develop colorectal cancer. GASTROCare® supports the recommendation of The Crohn's and Colitis Foundation of America that ulcerative colitis and Crohn’s disease patients get yearly screenings after having the disease for seven years.
Radiation for Prostate Cancer: Those having had this radiation have about a 70% higher risk of rectal cancer. The risk is similar to having a family history of the disease. GASTROCare® does not advise against the radiation; we advise more rigorous screening to reflect the additional risk.
Diabetes 2 and Insulin: Those who have received more than three years of insulin therapy have been shown to have more than three times the risk of those who did not. Do take insulin where needed, but screen more rigorously to reflect the added risk.
Other Genetic:
Seven to eight percent of colorectal cancer is caused by known colorectal cancer gene abnormalities. But it is currently thought that up to 20% or more of all colorectal cancers may be genetic.
For specific screening recommendations for high risk groups, click here
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More colorectal cancers are considered familial (family-related) than genetic. While all genetic cancer is familial, some familial cancers are strictly due to shared lifestyle and environmental factors. A genetic predisposition to cancer can be influenced by lifestyle factors.
Up to 5% of colorectal cancers result from inherited syndromes carrying an extremely high risk. These are:
Familial Adenomatous Polyposis (FAP) or its variation, Gardner’s Syndrome, where hundreds or thousands of benign colon polyps develop at a young age. As some polyps are expected to become cancerous, annual colonoscopies may be needed from childhood. Preventive surgical removal of the colon is usually recommended by the late teens to avoid the almost 100% risk of cancer. These rare syndromes cause less than one percent of colorectal cancers.
Hereditary Non-Polyposis Colorectal Cancer (HNPCC) or Lynch Syndrome is more common, associated with about 3-5 percent of colorectal cancers. People with HNPCC tend to develop a fast-growing cancer in their 40s and have a higher risk for other cancers. About 70 percent of gene-carriers develop colon cancer by the age of 80, and are advised to have annual colonoscopies starting from 25 or 40 depending on family history.
A genetic mutation affecting only Ashkenazi Jews was recently discovered. This syndrome is much less dramatic than FAP or HNPCC, but does double or triple the risk of colon cancer to 9 to 15%, along with a higher risk for certain other cancers. Ashkenazi Jews with first or second degree relatives with colorectal cancer are advised to start screening colonoscopies at age 35, repeating at three year intervals. A blood test can identify those with the responsible gene, allowing an aggressive screening regime. Studies are in progress to learn more about this form of inherited cancer.
| Contact us for genetic testing referrals. |
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