When to begin screenings for colorectal cancer

(Hint: It may be earlier than you think!)

Women holding anatomical model of colon against torso

March is National Colorectal Cancer Awareness Month. Many are surprised to learn that colorectal cancer is the third-leading cause of cancer-related deaths in women. To learn more about colorectal cancer prevention, we sat down with David Lieberman, M.D., who heads up OHSU’s Division of Gastroenterology and Hepatology. One of his passions is working to improve patient education and access to colorectal cancer screening.

Preventive screenings play a critical role in detecting colorectal cancer early. It is important to know when to begin screenings, what types of screenings are available and how often they should take place.

Change in screening guidelines

“Up until very recently, the recommendation was to begin screening at age 50, because the risk of colon cancer started at that age,” says Dr. Lieberman, “However, over the last few years, we have seen the risk of cancer go up before the age of 50.”

The American Cancer Society now recommends people at average risk of colorectal cancer begin screenings at 45 years old. Researchers have several hypotheses about why colorectal cancer is occurring in younger people. Increased use of antibiotics in childhood, obesity at a younger age, concerns about food additives or antibiotics, and even a sedentary lifestyle are factors that may have played a role. While researchers continue to sort out the cause, the effect is that the new guideline recommends moving colon cancer screenings to begin at age 45.

For anyone with a family history of colorectal cancer or other related diseases, screenings should begin even earlier. Talk to your provider if you are higher-risk. After age 75, patients should work with their providers to determine a screening plan.

Colorectal cancer screening tests

There are two primary types of screening for colorectal cancer used in the United States.

Fecal Immunochemical Test
Known by its acronym FIT, the Fecal Immunochemical Test is a stool-based screening that patients can do at home, using a kit prescribed by their provider. After collecting a stool sample, the patient sends the sample to a lab, where it is tested for microscopic amounts of blood. If the result is positive, the patient receives a referral for a colonoscopy. If negative, the recommendation is to do a FIT screening every year. This form of screening is non-invasive and inexpensive. There are other screening options that work in a similar fashion, but the FIT test is the preferred stool-based screening tool at OHSU.

A colonoscopy is the second screening option. Colonoscopies require a bowel prep. The patient is sedated while a doctor inserts a flexible tube with a camera into the colon to detect and polyps or growths.   The advantage to this form of screening is that colonoscopies can detect cancer and pre-cancerous lesions, such as polyps. Colonoscopies are recommended about every 10 years for average-risk individuals.

“Average risk does not mean low risk”

According to the American Cancer Society, the overall lifetime risk of developing colorectal cancer for women is about 1 in 25. Pre-menopause, women have a lower rate of colon cancer than men. Post-menopause, their risk of colorectal cancer follows the same curve as men, and increases with advancing age.

 “It should be noted that average risk does not mean low risk,” says Dr. Lieberman, “It’s important to talk to your health care provider about your screening, and this conversation should take place before age 45.”

“It’s also important for women to let providers know if there is a history of colon cancer in their family,” he adds, “If someone has a family history, then the risk for that woman doubles.”

Fortunately, the overall incidence of colorectal cancer in both men and women has been declining for the past 30 years. Much of this is likely due to improved screenings, a higher percentage of people completing their screenings, and early treatment of pre-cancerous findings.