At What Age Should I Begin Screening for Colorectal Cancer?
Colorectal cancer is the only type of cancer that is considered preventable. When polyps form in the colon and rectum, they can become colorectal cancer over time. By removing the polyp, you can prevent colorectal cancer.
That’s why screening for colorectal cancer is so important. The American Cancer Society recently lowered its recommended age to begin colorectal cancer screening from 50 to 45 for people of average risk. The guideline was changed due to new data showing a four-fold increase in colorectal cancer incidence among people under 50 years of age. At the same time, incidence has decreased for those 50 to 75 years of age, as colorectal cancer screening has increased for this population.
“Average risk” is defined as someone without any symptoms (bleeding, change in bowel habits), without a first-degree relative with colorectal cancer, no personal history of any diseases that would increase risk (such as inflammatory bowel disease or polyps) and with no known genetic syndrome (such as familial adenomatous polyposis or Lynch syndrome). Individuals with these conditions would need an
earlier and more aggressive screening regimen.
“Colonoscopy is the gold standard for colorectal cancer screening because it is the most accurate,” says Craig Rezac, MD, FACS, FASCRS, VHC Physician Group–Colorectal Surgery. “It is also the most therapeutic because if we find polyps, we can remove them during the procedure.”
There are other methods of screening for colorectal cancer, including at-home tests and a virtual scan.
While there are several kinds of at-home tests, the only one Dr. Rezac recommends is a DNA test, such as Cologuard®. “Polyps develop and become cancer over time through a sequence of mutations in the cell. As the polyp grows, cells slough off and are eliminated in stool. Doing a DNA test on stool can detect mutations that are occurring and identify cancer early. However, this test is not appropriate for people who have had polyps in the past,” says Dr. Rezac.
CT colonography is a non-invasive scan, and requires the same bowel preparation as a colonoscopy. It is more sensitive than the DNA stool test, but not as sensitive as a colonoscopy.
If the results are positive from either of these methods, the patient must follow up with a colonoscopy. “In half of colorectal cancer cases, the diagnosis is not made until the cancer has reached an advanced stage. With earlier screening beginning at age 45, colorectal cancer can be prevented, or if detected early, cured in more people,” says Dr. Rezac.