Millions of people who thought colorectal cancer screening was somewhere off in their distant future recently got a wake-up call.
The recommended age for taking one of the available tests was lowered to 45 years from 50, suddenly pushing the next generation of people into the group of those who should be screened.
Colorectal cancer kills more people than any other cancer that’s not directly related to smoking, with men and women similarly affected. While it is most frequently found in older people — those between 65 and 74 account for the largest number of diagnoses — cases have been surging among people decades younger than that. Some 18,000 Americans under 50 are expected to be diagnosed with colorectal cancer this year (1).
That prompted the U.S. Preventive Services Task Force in May 2020 to follow the lead of the American Cancer Society and other physician groups in recommending that screening begin at 45 for people at average risk. Those with added risk factors, such as certain inflammatory bowel diseases or having close relatives with colorectal cancer, should consider starting even earlier.
Why is this deadly cancer increasing in people under 50? Researchers still aren’t sure. However, some of the same lifestyle factors that fuel the obesity epidemic are prime suspects. Recent studies have shown that greater consumption of red meat (such as beef and pork), sugary drinks, and alcohol are associated with the increase in cancer for younger people, though the research falls short of proving a direct cause-and-effect link (2, 3).
Now, some 21 million people are for the first time facing a decision about which screening method they should use.
Non-invasive tests — meaning those that do not require a medical procedure such as colonoscopy — have been steadily improving over the years, creating additional options. So which test is best for you? Here are snapshots of three frequently used tests:
Colonoscopy: This is the standard to which other tests are compared and the most frequently used. A doctor uses a flexible tube with a camera on it to travel the 5-foot length of colon looking for the polyps that can develop into cancer. One great advantage of this test is that it allows a doctor to remove any polyps found immediately, preventing any from developing into cancer. Disadvantages include the necessary sedation, which means some might miss a day of work and all need to be accompanied home. It also requires “bowel prep,” a cleansing of the colon that many people find uncomfortable. After a negative test, the next one need not be done for another 10 years.
Cologuard: This is the brand name of a test also called multi-target stool DNA (mt-sDNA). Developed by a team that included a Mayo Clinic physician, this widely advertised test can detect subtle genetic changes that occur in precancerous polyps and cancer. Like older tests, Cologuard also looks for hidden blood, a finding in cancer. It requires a patient to submit an entire stool sample by mail for testing – a collection kit is included. The test should be taken every 1 to 3 years, and a positive test must be followed by a colonoscopy. Of note, insurance coverage of the follow-up colonoscopy after a positive result from a stool-sample screening test can vary, so ask for details of your coverage with your insurance plan before trying mt-sDNA testing.
FIT: The fecal immunochemical test (FIT) detects blood in a small sample of stool collected at home and mailed to the lab. It does not detect most polyps, the precursors to cancer, so it must be repeated every year. A positive test must be followed by a colonoscopy.
Dr. Stephanie Hansel, a gastroenterologist at the Mayo Clinic, recommends that everyone between the ages of 45 and 75 discuss their options with their health care provider, because each method has plusses and minuses.
“Colonoscopy – if we can get people doing it – has the advantage of being diagnostic and therapeutic, because polyps can be removed,” she said.
“The biggest advancement in screening is the Cologuard test, at least giving us a better non-invasive test,” she said.
Ultimately, Dr. Hansel said, the crucial thing is that people take some screening test on the recommended interval.
Stephanie L. Hansel, M.D., M.S.
Dr. Hansel is a gastroenterologist, with clinical interests common gastrointestinal disorders such as diarrhea, constipation and irritable bowel syndrome, and in interpretation of capsule endoscopy imaging and in routine endoscopic procedures. In addition to her clinical activities, Dr. Hansel is active in education and research.