Colorectal Cancer Screening and Prevention

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Screening and prevention of colorectal cancer continues to improve, according to Daniel Haller, MD. The latest annual American Cancer Society report noted that colon cancer incidence in the United States declined by roughly 20% over the last decade. This is exciting, since the incidence of colon cancer would be expected to continue to rise in an aging population, Haller states. Overall, more than half of people are getting colonoscopies and having their polyps removed.

The reduced incidence of colon cancer is related to a combination of multiple known and unknown factors that include early detection and lifestyle changes, such as getting more exercise, increasing vitamin D intake if appropriate, and taking aspirin. The most important factors remain colonoscopy and lifestyle, emphasized Herbert Hurwitz, MD. Regarding screening tests, colonoscopy remains the “gold standard” in the United States and extra effort should be made to make it available to everybody, Hurwitz continued.

While several available new screening tests are useful, such as one developed at the Mayo Clinic that looks at molecular profiling in the stool, these should be considered companion tests to colonoscopy-based screening. According to John Marshall, MD, half of his patients are now under 50 years of age. In terms of colon cancer incidence, this is the group of patients that is increasing the fastest.

With so many people in their 30s and 40s being diagnosed with colon cancer, 50 may no longer be the best age to start screening. Alan Venook, MD, feels that we first need to succeed in screening those who are at greatest risk, and the median age of diagnosis is still in the late 60s. He recommended to stick with age 50 for now.

At this point, it may not be efficient to begin screening those below the age of 50; however, researchers have begun to identify who should be screened at a younger age and “at-risk” populations—for instance, those with family risk. The weakest part of the analysis for many patients is, “What’s the family risk?” The most obvious, but also the least expensive, screening tool is talking with the patient and taking a good family history, added Haller.

Patients who are under 50 do not get screened routinely, but there are efforts to get away from the fixed 50-years-of-age threshold for screening in that population. Grothey notes that more evidence is need before researchers can claim that there is a change in biology—something is going on and it probably has to do with obesity, alcohol consumption, or other lifestyle changes.

When asked about direct-to-consumer genomic screening tests and whether a person can find “at-risk” genes that may lead them to earlier screening, Axel Grothey, MD, emphasized that these tests should not be recommended because the results are difficult to interpret. Grothey agrees with Venook that emphasis should be on what works—established screening tools.