Colon cancer is the third-leading cause of cancer deaths for both men and women in the United States. Colon cancer is often referred to as colorectal cancer, because colon cancer is often present in the rectum as well. However, it is possible to have rectal cancer alone, but the comorbidity of rectal and colon cancer together is very high. While the mortality rate of colon cancer has been decreasing due to diagnostic testing such as colonoscopy, if colon cancer is not detected early, the mortality rate is exceptionally high. For example, a patient with stage IV colon cancer has a 12 to 14 percent five-year survival rate. If colon cancer is discovered while it is still localized (stage I), patients have a 91 percent five-year survival rate.
Looking at the statistics reveals that early detection is crucial—and saves lives. Colonoscopy is the gold standard for early detection of colon cancer, but family history is important too. While researchers have not pinpointed the exact cause of why colon cancer develops, there is a definitive hereditary link. Also, certain forms of colon cancer are clearly linked through genetics, such as Lynch syndrome.
Colorectal cancer is one of the deadliest cancers because, in most cases, patients are asymptomatic. When someone begins to feel symptoms of colon cancer, it’s typically a sign that the cancer has progressed to later stages, such as spreading to the lymph nodes or vital organs. In these stages, the mortality rate increases significantly. It’s important to inform your doctor if you have any immediate family history of colon or rectal cancer, polyps, and other gastrointestinal conditions such as inflammatory bowel disease (IBD). The American Cancer Society recommends that both men and women have their first colon cancer screening at age 45. However, if you have risk factors such as an immediate family history of colon cancer, you have a greater risk of developing the cancer earlier. Those with a family history of colon cancer can opt for genetic testing, to be screened for colorectal cancer earlier than 45, or both.
Your healthcare provider may recommend genetic testing If you have a noted family history of colonic cancers or GI conditions. There are specific types of colon cancer that are hereditary, including Lynch syndrome (hereditary non-polyposis colon cancer), familial adenomatous polyposis (FAP) or attenuated FAP (AFAP), Gardner syndrome, Peutz-Jeghers syndrome, and MUTYH-associated polyposis (MAP).
Many cases of colon cancer stem from these acquired gene mutations. However, patients will be asymptomatic and may not know they have mutated genes present.
If you meet certain criteria and risk factors for colon cancer, you can opt for genetic testing prior to a colon cancer screening. Predictive genetic testing looks for acquired mutated genes, putting a person at a higher risk of developing colon cancer. The genetic testing itself is a simple process. First, you will meet with a genetic counselor to discuss the test and advise you of what to expect. Then, you will submit either a saliva swab or have a blood test to determine if you have any of the known hereditary colon cancer gene mutations.
Some patients opt for genetic testing, some opt for early screenings, and some opt for both. Your gastroenterologist may order different diagnostics based on your individual case. Some of the diagnostic tests may include:
If genetic mutations or colon cancer are discovered, your gastroenterologist will then discuss the next steps or treatment options.
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