Are At-Home Colorectal Cancer Screening Tests Worth the Buzz?...YES

If you’ve been watching television, browsing the internet or reading a magazine recently, you may have come across mentions of a newer category of colorectal cancer screening: at-home tests.

These tests, which have been growing in popularity over the last few years, are less invasive than and don’t require the same preparation as colonoscopy (one of the most well-known and common colorectal screening tests in the United States).

While there are some benefits to at-home colorectal screening tests, there are also limitations and things you should consider before ordering one.

To help you weigh the pros and cons, colon and rectal surgeon John Park, MD, with Colon-Rectal Surgery Associates, PC, answers common questions about this screening option:

At-home colorectal cancer screening tests, also known as stool-based tests, involve collecting a sample of your poop and mailing it to a lab for analysis. A positive finding could mean that you have precancerous polyps (growths) or colorectal cancer.

There are three main tests that fall into this category:

• Guaiac-based fecal occult blood test (gFOBT): The least common (and least accurate) of the at-home options, this test looks for blood in your stool, but can’t reliably differentiate between human blood and animal blood. Because of this, you must avoid eating certain foods and avoid taking some medications and supplements for a period of time before collecting your sample. It’s recommended that this test is repeated annually.
• Fecal immunochemical test (FIT): This test also looks for blood in your stool, but can differentiate between human and animal blood, so you don’t need to avoid certain foods or medications/supplements beforehand. Like the gFOBT, it should be repeated annually.
• Stool DNA test: The latest and most advanced at-home option, this test looks for human blood in your stool and also abnormal DNA that is shed by colorectal cancer or advanced precancerous polyps in the colon. It should be repeated every three years.

“Because these tests can be done from the comfort of home and don’t require you to clean out your colon beforehand, they are becoming more popular,” Dr. Park says. “However, while convenient, they don’t quite match up to colonoscopy.”

Like at-home screening tests, colonoscopy looks for colorectal cancer and precancerous polyps. However, the test itself is done at an outpatient medical facility, and you are put under sedation while a tube with a camera is inserted into your rectum and moved throughout your colon. A bowel preparation is required beforehand, which involves a clear liquid diet, drinking a lot of fluids, and taking laxatives.

While colonoscopy is certainly more involved than at-home screening tests, it is more beneficial in many ways.

“While the stool DNA test, which is the most advanced of the at-home options, is more than 90 percent effective at detecting cancer, it’s only about 40 percent effective at detecting precancerous polyps,” Dr. Park says. “Colonoscopies are also more than 90 percent effective at detecting cancer, but somewhere between 75 and 80 percent accurate at detecting polyps. Clinicians are also able to remove the polyps they find during the test, which prevents them from becoming cancerous in the future.”

It’s also important to note that at-home screening tests are not meant for individuals who are at higher risk for colorectal cancer due to a family history of the condition, a history of precancerous polyps or inherited cancer syndromes. Also, if your at-home test comes back positive, you will need to receive a colonoscopy anyway for further diagnosis and/or removal of polyps.

“Colonoscopy is the gold standard for colorectal cancer screening,” Dr. Park says. “No one likes the bowel preparation, but it’s worth it for the chance to detect, and in many cases prevent, such a dangerous condition.”

For the most part, colonoscopies also don’t need to be repeated as often as at-home screening tests.

"For average risk patients, if nothing is found during their colonoscopy, they won't need another for 10 years,” Dr. Park says. “If polyps are found or if they’re at higher risk in general, it may be recommended that they get another one sooner, perhaps in three to five years, depending on their situation."

If you are age 45 or older and due for a colorectal cancer screening, talk to your doctor about next steps and which type you are interested in.

“While there are many reasons we suggest colonoscopy over other options, it’s true that the best screening test is the one that gets done,” Dr. Park says. “If you are interested in at-home testing, your doctor can help you determine if you are eligible and make sure you understand all of the pros and cons.”