The Numbers: Colon and rectal cancers account for 13% of all cancers diagnosed each year. The good news is that the number of cases diagnosed has dropped dramatically since 1975, and the death rate has gone down by almost half. Still, 26,470 men in the U.S. died as a result of colon and rectal cancer in 2012, according to the American Cancer Society
Risk Factors: Certain inherited genetic mutations such as Lynch syndrome and hereditary polyps can increase a person’s risk of colorectal cancer, but 75% of tumors appear to occur without those factors. Eating a low-fiber diet that’s high in red meat seems to increase the risk somewhat, but other causes are still unknown.
Symptoms May Include: a change in bowel habits, blood in stools, fatigue, unexplained weight loss, vomiting, and general abdominal discomfort.
How It Progresses: Bowel cancer can spread through the walls of the colon into the surrounding lymph nodes and eventually the liver.
Screening Tests: There are three primary tests for bowel cancer: colonoscopy, sigmoidoscopy, and high-sensitivity fecal occult blood testing. “They are all effective, and I’m neutral as to which one to recommend,” LeFevre says, adding that it’s a matter of talking to your doctor to determine which option is best for you.
A colonoscopy should be performed every 10 years. “The transition from a normal colon to one with a cancerous polyp is a slow process,” LeFevre says, explaining why being tested only once each decade is usually sufficient to find polyps and remove them before they become cancerous.
The downside to a colonoscopy is that the preparation is arduous and requires “cleaning out” the colon by drinking gallons of liquid, which can cause cramping. Patients are sedated for the actual procedure to prevent discomfort, but in rare instances complications such as tears can occur.
A sigmoidoscopy is easier and has fewer risks than a full colonoscopy. The test covers only the first third of the colon, and should be done every five years. If a polyp is found, a full colonoscopy is then performed.
The last option is an annual stool test. This high-sensitivity test checks for blood in the stool; if any is found, a colonoscopy is then ordered. A stool test is not nearly as obtrusive as a colonoscopy, but it can be challenging to remember to have it done every year.
In the future, undergoing a virtual colonoscopy—in which a three-dimensional image of the colon and rectum is taken—may also be an option, but as of now, it’s still unclear whether this test is as accurate as the aforementioned traditional colonoscopy.
Should You Get Screened? Screening is a huge factor in reducing deaths from colorectal cancer. “Everyone should get regular screening by age 50,” LeFevre says. “If you’ve had a first-degree relative with this cancer, start screening 10 years prior to the age when that person was diagnosed.”