At-home test can more accurately diagnose colon cancer

An at-home test can accurately detect colorectal cancer nearly 80 percent of the time, according to a new study, representing a significant jump from older tests that could identify the deadly disease less than half the time.

The test, which involves submitting a stool sample each year to have it analyzed for the presence of blood, is far more accurate than a more widely-used, older test – 79 percent accuracy in detecting colorectal cancer versus between 13 and 50 percent of the time.

Colorectal cancer is second only to lung cancer in causing cancer-related deaths in the U.S, killing more than 50,000 people each year, and makes up nearly 9 percent of all new cancer cases, according to the National Cancer Institute.

In recent years, increased awareness of the need for adults over age 50 to regularly screen for colon and rectal cancers has saved a lot of lives, but the screening process itself isn’t pleasant.

You can either elect to get a colonoscopy every 10 years, which involves being anesthetized and having a doctor insert a camera into your colon. Or, you can take a less invasive approach that must be done each year: submitting a stool sample each year to have it analyzed for the presence of blood.

Either way, the process isn’t fun. But a review of the research on the latter approach, a newer version of the test called a fecal immunochemical test (FIT), shows it can accurately detect colorectal cancer about 80 percent of the time, according to a new study released Monday. Older, more widely used versions of the test only detect the cancer between 13 percent and 50 percent of the time.

“It’s a user-friendly test,” said Dr. Jeffrey Lee, a physician at the Kaiser Permanente Division of Research in Oakland, Calif. and lead author of the study. “You do it in the privacy of your own home; you don’t have to do it at the doctor’s office.”

In the study, which was published in the Annals of Internal Medicine, researchers reviewed 18 different studies of nine different brands of FITs. They found that on average, FITs were able to accurately detect colon cancer 79 percent of the time in just a single round of testing.

The older version of the test, which is used much more widely in the U.S., Lee said, is only able to detect colorectal cancer between 13 percent and 50 percent of the time — meaning the older test can miss the cancer at least half the time.

What’s more, the older test is done in three rounds, to achieve more accurate results, and also has certain dietary and medication restrictions — eating red meat or taking aspirin, for example, can create a false positive.

As a result, Lee said, while the older test is more commonly used in the U.S., he thinks it should be phased out in favor of FITs among those patients who aren’t able to take the time off work to get a colonoscopy.

He did note that his study did not compare FITs to colonoscopies in terms of accuracy in detecting colorectal cancer, and that if the FIT result is positive, a person would have to get a colonoscopy anyway.

If patients want to know which test they should choose, though, he said, “Ultimately, the best screening test is the one that gets done.”