By Matt Smith
WebMD Health News
Reviewed by Michael W. Smith, MD
July 27, 2016 -- Up to 40% of people who should get a test for colon cancer aren't doing so.
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That's one of the reasons why some doctors are encouraged by Cologuard, a new at-home test for colon cancer.
The mail-away DNA stool test for colon cancer is covered by Medicare, and an influential federal task force just included it on a list of recommended ways to look for the disease. However, at $649, it's more expensive than older tests that look for signs of colorectal cancer in a stool sample. It doesn't have the established track record of older tests, and it won't find growths in the colon the way a colonoscopy will.
But when millions of people aren't getting tested for one of the most common and preventable forms of cancer, doctors say its convenience may help close that gap.
"Of course, as a gastroenterologist, I prefer a colonoscopy," says Carol Burke, MD, vice chair of gastroenterology and hepatology at the Cleveland Clinic. "But the bottom line is 40% of the population hasn't been screened. This is a preventable disease."
Doctors consider colonoscopy the best way to look for colon cancer, since it can find and remove nearly all abnormal growths. But the dreaded "prep" can take a day or two and involves cleaning out the colon with laxatives. During the procedure, doctors insert a camera-equipped probe into the colon to look at its inner lining.
The test can cost more than $2,000 without insurance, although it's usually covered as a screening test.
Unlike older stool tests that look for traces of blood -- a potential warning sign of colorectal cancer --Cologuard looks for abnormal cells associated with cancer and precancerous polyps. Patients receive a test kit, pack up a stool sample at home, and mail it to the company's laboratory, which sends the results to the patient's doctor.
The FDA approved it in August 2014 after a study of nearly 10,000 people conducted by the test's manufacturer, Wisconsin-based Exact Sciences. In that study, Cologuard detected 92% of colorectal tumors and 42% of precancerous growths.
In comparison, the more common fecal immunochemical test, which looks for blood in the stool, found 74% of cancers and 24% of precancerous growths.
Cologuard had a higher rate of false positives than the blood test, however: about 13% compared to 5%, according to the FDA. A false-positive result suggests cancer when it's not there.
"At the moment, it seems to be a very promising test. Patients seem excited about it and motivated," says Aasma Shaukat, MD, assistant professor at the University of Minnesota's medical school. "Providers are a lot more cautious, and everybody would like to see more conclusive data -- ideally from studies showing that it actually saved lives and reduces the risk of developing or dying from colon cancer."
Exact Sciences CEO Kevin Conroy says the company tested more than 104,000 people in its first year. Of those, 42% had never been tested. "We are expanding the screening population, which is one of the goals we set out 7 years ago when we embarked upon this journey."
One of the doctors singing its praises is Cynthia Rudert, MD. Rudert calls Cologuard "one of the best advances in medicine in the past decade." Its reliance on DNA makes it more likely than other stool tests to spot precancerous lesions that aren't yet bleeding, she says.
"It is far superior, and it's very unusual to say the least -- unheard of, actually -- that the day the Cologuard was FDA-approved, Medicare approved it. They know that colon cancer is over an $18 billion industry when you count chemotherapy, radiation, surgery, etc. And 70% to 80% of that money is Medicare dollars."
Medicare, the federal health insurance program for seniors, will pay for the test every 3 years. Private insurers have been slower to adopt it. On its website, Exact Sciences lists three dozen companies that cover Cologuard, including national giants Aetna and Anthem Blue Cross/Blue Shield. But Conroy said the combination of public and private plans means about 57% of the population in need of screening --about 52 million people between ages 50 and 85 -- can get the test.
That may go up after this summer. In June, the U.S. Preventive Services Task Force, which recommends procedures to be covered under the Affordable Care Act, included Cologuard on a list of accepted tests for colorectal cancer for people over 50. The National Committee for Quality Assurance, a nonprofit organization that collects data on health-care effectiveness, says it is updating its recommendations for colorectal cancer screening and may include Cologuard.
The American Cancer Society notes the at-home test isn't for everyone. It's only for people with an average risk of colon cancer and no history of precancerous polyps, colon cancer, or some other colon problems.
And any test shows signs of cancer needs to be followed up with a colonoscopy. That can lead to insurance complications for patients, Burke says. If the Cologuard test finds cancer, a patient then has to get a follow-up colonoscopy. At that point, the colonoscopy is likely to cost more since it's not considered a screening test, Burke says.
Nevertheless, Shaukat says more than two dozen of her patients have asked about Cologuard in the last 6 months. She said further studies will be needed to gauge Cologuard's effectiveness as the test becomes more widely used. But for now, "the best screening test is the one that gets done."
SOURCES: FDA: "Summary of Safety and Effectiveness Data, Cologuard." Imperiale, T. New England Journal of Medicine, April 2014. U.S. Preventive Services Task Force: "Final Recommendation Statement, Colorectal Cancer: Screening, June 2016." Center for Medicare Services: "Decision Memo for Screening for Colorectal Cancer - Stool DNA Testing (CAG-00440N)," October 9, 2014. Exact Sciences Corporation. Carol Burke, MD, vice chair of gastroenterology and hepatology, Cleveland Clinic. Aasma Shaukat, MD, MPH, assistant professor at the University of Minnesota Department of Medicine. Kevin Conroy, chairman, CEO, and president, Exact Sciences. Cynthia Rudert, MD, Atlanta. News release, FDA.
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