Annual At-Home Tests Just as Effective as Colonoscopies at Detecting Cancer

Experts say doing the stool sample tests every year is as accurate at detecting colorectal cancer as a colonoscopy every 10 years.

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The at-home stool sample tests are inexpensive and easier when compared to the rigors of a colonoscopy. Getty Images

You can get one really accurate and really easy test every year. Or you can get one really, really accurate but uncomfortable and inconvenient test every 10 years.

That’s essentially the choice facing people over 50 when it comes to detecting colorectal cancer.

While colonoscopies have been widely recommended for the past two decades, a much simpler stool sample test is nearly as effective at detecting colorectal cancer, new research finds.

That confirms what many colon cancer experts have been saying for years — especially since large numbers of patients don’t follow up on colonoscopy recommendations.

Colonoscopies are still the gold standard, but there are other options. And, experts say, a stool-sample test done every year is as good as a colonoscopy done every 10 years.

“When you test every year, the outcomes are very close to what you get with colonoscopies,” Robert Smith, PhD, vice president of cancer screening at the American Cancer Society, told Healthline.

It’s also a lot less painful on the wallet, schedule… and body.

“There are a lot of people in the U.S. who simply don’t have access to colonoscopies because of geography or poverty. And there’s a significant proportion of the population who doesn’t want a colonoscopy” because they’ve heard bad things or know it’s unpleasant, said Smith.

He would like patients to know of all the options that are available.

Dr. Thomas Imperiale, who studies colon cancer screening at the Indiana University Medical Center and was lead author of the new study, agrees.

“It’s not a matter of (replacing). It’s a matter of providers offering patients a choice when it is appropriate to do so,” Imperiale told Healthline.

He added that he thought the stool-sample tests should be recommended more often than they currently are.

Imperiale said that choice would be appropriate for the 85 percent of the population who are at average risk of colon cancer. That includes people without a previous colon cancer diagnosis, a history of an inflammatory bowel disease, a sibling or parent diagnosed with colon cancer before age 60, or two or fewer relatives diagnosed at any age.

If you don’t have those risk factors, a simpler, more frequent test could be an easier option than a colonoscopy.

What test is best?

Imperiale’s study reviewed previous studies of the effectiveness of fecal immunochemical tests, but there are a number of different kinds of the fecal tests as well as other similar types of exams.

That’s where things get complicated.

The individual tests range in accuracy, Smith said, but that shouldn’t scare people away from using them. And, he noted, the clinic or hospital will already have a particular test they use, so patients likely won’t get a choice between tests anyway.

“What we don’t want is to have the doctor recommend a colonoscopy and then the patient doesn’t do it,” he said.

Instead, he wants more people to use one of the types of stool-sample tests.

Those include the fecal tests as well as high-sensitivity guaiac tests, which both test for blood in the stool that would be invisible to the human eye. In addition, there is Cologuard, a once-every-three-years test that looks for changes in the DNA in stool that have been associated with colon cancer or polyps.

Typically, these tests involve collecting a stool sample at home and bringing it to a lab for analysis.

The new study found that fecal tests do well at detecting cancer but not necessarily polyps, which can sometimes become cancerous.

However, most polyps never become cancerous, Dr. James Allison, a gastroenterologist at the University of California, San Francisco, and Kaiser Permanente Northern California’s Division of Research, told Healthline.

There are other potential drawbacks. Colonoscopies accurately detect cancer and large polyps about 95 percent of the time. Imperiale said a single fecal test is around 75 to 80 percent.

But since those tests are repeated annually that percentage can go up over time. And 75 to 80 percent is much better than not getting screened at all because of costs or concerns over a colonoscopy.

A fecal test costs about $25 to $30, Imperiale said.

The fecal tests “are as good applied either every year or every other year as colonoscopies every 10 years,” Allison said. “I’ve been saying it and it’s getting more fans.”

That’s already the policy in many other countries, he noted.

Canada, for instance, has decided there is insufficient evidence to justify routine colonoscopies for screenings and instead recommends a stool-sample test every two years.

The bottom line

New research confirms that yearly stool sample tests be used more widely to screen for colorectal cancer.

Since they’re done every year, the easier, cheaper tests are as effective at detecting cancer as a colonoscopy done every 10 years.

The annual tests can help ease the problem of people deciding not to get colonoscopies due to their expense and/or unpleasant experience.