Contributed by William E. Karnes, MD
Colorectal cancer is the second leading cause of cancer death in the U.S. And although there is no single cause, one in 24 people will be diagnosed with this disease in their lifetime. Did you know that certain factors can push this risk even higher — even up to 100 percent? Having these risk factors on your radar from a young age will allow you to be your own advocate and be proactive about your health and screenings.
The Subgroup Breakdown
There are three subgroups of risk — sporadic, familial, and hereditary. If you fall into the sporadic group, which means you have no family history of cancer or inherited genetic predisposition, you have a 3 to 7 percent lifetime risk of getting colorectal cancer. If you have familial risk, a single first-degree family member (parent or sibling) with colorectal or endometrial cancer under age 50, your lifetime risk increases to 10 to 20 percent. Family history is an important indicator not only because of shared genes, but similar lifestyles, too.
Those who have the highest lifetime risk of colorectal cancer are in the hereditary subgroup. Depending on the particular genetic syndrome, including Lynch, FAP, MAP, Peutz-Jegher’s, and others, the chances of getting colorectal cancer may be 30 - 100 percent. If you have a family history, talk to your doctor!
Factors You Can’t Control
All colorectal cancers are caused by gene mutations. Your risk increases with age because new mutations accumulate as we get older, which is why the majority of colorectal cancers occur after age 50 (males slightly earlier than females.) African-American males tend to get colorectal cancer a bit earlier, and Asians and Hispanics a bit later. Certain inherited mutations can cause colorectal cancer to develop at much younger ages.
… And Those You Can
So what can you do? You can reduce your risk of colorectal cancer by limiting your intake of red and processed meat, staying lean, exercising, limiting alcohol consumption, and by not smoking. You also reduce risk by controlling and treating conditions like inflammatory bowel disease or type II diabetes.
Screening Saves Lives
Fortunately, most colorectal cancers are preventable through lifestyle changes and the removal of precancerous polyps through screening. Colonoscopy is the gold standard for finding polyps and the only test that allows for their removal. The best chance of preventing colorectal cancer, even for those with an inherited syndrome, is to follow the recommended guidelines for colonoscopy. No matter which risk subgroup you fall into, colonoscopy and removal of polyps can reduce your risk for colorectal cancer by an additional 70 to 90 percent!
Dr. Karnes is a fellowship-trained gastroenterologist who specializes in disorders of the gastrointestinal tract, with an emphasis on colon cancer screening and identifying patients and families with a genetic risk for developing the disease. He also conducts translational research on colon cancer prevention.
Take our colorectal cancer screening quiz, and don’t forget, the Colorectal Cancer Alliance serves as a source of information about colorectal health. If you have additional questions about colorectal cancer screening or are in need of support, please contact our free Helpline at (877) 422-2030.
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