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New guidelines offer a variety of screening tests for colorectal cancer, some of them noninvasive.
AFTER AMANDA HOUSTON WAS diagnosed with colon cancer at the age of 34 in 2013, her mother made an appointment for her first colonoscopy at age 60 — a full 10 years after oncologists generally recommend that patients start regular screening for colorectal cancer. Houston’s mother turned out to also have the disease, but her cancer was in a far more advanced stage, requiring surgery and 12 rounds of chemotherapy. Houston, a human resources professional in Fargo, North Dakota, was treated successfully with surgery alone.
Both mother and daughter are now clear of the disease, but the difficult experience has turned Houston into a proponent of regular screening for colorectal cancer. “I really don’t know why my mother put it off,” Houston says. “If she had been screened at 50, maybe her cancer would have been prevented or caught at a much earlier stage.”
Colorectal cancer screening is becoming easier and more accessible, thanks to updated federal guidelines implemented in the summer of 2016. The guidelines were issued by the United States Preventive Services Task Force (USPSTF), which makes health care recommendations that insurers consult when determining which procedures they will cover. The new guidelines, an update of 2008 recommendations, embrace a variety of screening tests beyond colonoscopy, some of which are noninvasive and easy to perform at home.
That’s important, because many resist colonoscopy due to its downsides, which include the need to fast and clear out your digestive system beforehand, and to be put under with sedation or general anesthesia for the test itself. About a third of eligible adults have never been screened for colon cancer, according to data collected by the USPSTF, and the agency estimates that 134,000 people were diagnosed with the disease in 2016 and 49,000 lost their lives to it. Yet several studies have demonstrated that colonoscopy and the other colon cancer screening tests have reduced the number of deaths attributable to the disease. The tests are important for everyone eligible, regardless of prior cancer status.
“I don’t care which test you get, I just want you to be screened,” advises John Marshall, M.D., director of the Ruesch Center for the Cure of Gastrointestinal Cancers at Georgetown University. The new guidelines, he adds, “should further close the gap and increase the participation of people” who are eligible for colorectal screening but have not yet opted for it.
The revised USPSTF guidelines award “A” grades to six colorectal screening tests and one combination of two of the methods for people between the ages of 50 and 75. Three of the strategies are at-home stool-based tests. Two of those tests, guaiac-based fecal occult blood test (gFOBT) and fecal immunochemical test (FIT), are designed to find blood in the stool, which can be an early sign of precancerous polyps or cancer. Patients who test positive would then be sent for colonoscopies to finalize the diagnosis.
The USPSTF found six randomized controlled trials showing that gFOBT tests lowered the risk of death from colorectal cancer by 32 percent when performed every year, which the agency recommends; a separate study that used predictive models found that FIT tests bested gFOBT tests when it came to life-years gained versus the burdens and harms of screening. Four trials of a more invasive test called flexible sigmoidoscopy — which does require bowel cleanout but not anesthesia — found a 27 percent decrease in the risk of dying from colon cancer — when test takers were assessed 11 to 12 years later — with just one screening. Randomized trials of colonoscopy have not been completed, but combined data from the Nurses’ Health Study and the Health Professionals Follow-up Study, which track participants over several years, found an association between colonoscopy and reduced mortality from colorectal cancer.
A new stool test that’s included in the USPSTF’s recommendations combines blood detection with DNA testing, which is designed to find genetic abnormalities that commonly signal the presence of polyps or cancer. A trial of the test, called Cologuard, in nearly 10,000 people, most without colorectal cancer or precancerous polyps, found that it detected cancer with 92.3 percent sensitivity, versus just 73.8 percent sensitivity with standard FIT testing. And the Cologuard screen may be effective when done every three years instead of annually, the USPSTF advises.
One negative of Cologuard, the USPSTF notes, is its higher rate of false positives than other tests, meaning the chances of being sent for a colonoscopy that ends up not finding cancer are higher for people who opt for this test over older FIT screens. That being said, the rate of false positives was higher for people over age 65 than it was for younger patients, says Thomas Imperiale, M.D., professor of gastroenterology and hepatology at Indiana University’s medical school and the lead author of the Cologuard trial. In light of that finding, Cologuard may be a good choice for people between the ages of 50 and 64 who are reluctant to undergo colonoscopies, Imperiale suggests. “This is a subgroup of people who are generally active, they may be raising teenagers, they’re working full-time and maybe they prefer not to have a colonoscopy,” he says. “But they may be more willing to get screened noninvasively with a test that looks for occult bleeding and mutations in DNA.”
The “A” grade on Cologuard and other non-invasive tests is unlikely to sway a physician’s advice to patients about which tests they should have, but it could make insurers more likely to reimburse for the tests, as payers tend to follow USPSTF guidelines when determining what to cover. Coverage by private insurers for colorectal screening varies, according to the American Cancer Society. Medicare covers almost all of the recommended tests, including Cologuard, at no cost. However, if during a colonoscopy a polyp is removed for further diagnosis, Medicare and other insurers might not cover that.
The USPSTF made clear that its screening recommendations apply to healthy people with no family history of colorectal disease. Anyone who has had two or more close relatives who developed colon cancer, or one who had the disease when they were younger than 60, is generally steered toward colonoscopy rather than the less invasive tests, Imperiale says.
Some genetic disorders predispose people to colon cancer, particularly Lynch syndrome. Patients can undergo genetic testing for the disorder, and those who have it should opt for colonoscopies at intervals recommended by their physicians, Marshall says. Still, the less invasive tests may be appropriate for people whose genetic risk is less clear-cut and who are resisting colonoscopy. “If you had an uncle or a parent who had colon cancer at age 60, we know you’re at some increased risk. And the gold standard has been colonoscopy,” Marshall says. “But these other techniques could help in those patients, as well. Anything that gets you tested is better than not doing anything at all.” Colon cancer is about 30 to 40 percent more prevalent in men than it is in women, and incidence and death rates increase with age, according to the American Cancer Society. The disease is most prevalent in African American men and women, leading the American College of Surgeons to recommend that screening in that population begin at age 45.
The best strategy for anyone who has been putting off colorectal screening is to start by consulting their physician, advises Anjee Davis, president of Fight Colorectal Cancer, a Springfield, Missouri-based national advocacy group. “Given the menu of options patients have available to them, it’s important to have discussions with their physicians to determine the best fit, in light of their family history, possible risk factors and insurance coverage, Davis says. And regardless of age or demographic group, anyone who has unexplained gastrointestinal symptoms should consider colorectal screening. Colorectal cancer is becoming more prevalent in adults under age 50, according to the American Cancer Society, for reasons that are unclear. That makes vigilance that much more important — and easier, now that a wider variety of tests is being offered by physicians and insurers. And whenever a colonoscopy is recommended, patients shouldn’t fear the procedure, advises Houston, who has the test every 18 months to ensure her cancer hasn’t returned.
“Find a good book, find something to binge watch on Netflix,” she says of the preparation process. “It’s 24 hours of mild discomfort. It’s lifesaving.”