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Colon cancer is the second-leading cause of cancer-related death following lung cancer1, but it is one of the most preventable cancers — if you get screened. A colon cancer screening allows your doctor to detect colon cancer and find abnormal growths that could become cancerous many years later.

“Screenings are the most important tool for reducing the incidence and death rate of colon cancer,” said Kirk Ludwig, MD, colorectal surgeon and chief of colorectal surgery with the Froedtert & the Medical College of Wisconsin Cancer Network. “When we find colon cancer in its early stages, treatments are very effective.”

Colon cancer starts out as a pre-cancerous lesion on the lining of the colon, called a polyp. Routine screenings are recommended for people at average risk beginning at age 50, but according to the Centers for Disease Control and Prevention, only 67 percent of Americans are up-to-date on their screenings.2 

Types of colon cancer screening

Several tests can be used to find polyps or colon cancer. You can do some of them at home; others require a clinic setting due to the type of technology involved. At-home tests are stool-based, whereas tests done in a clinic allow for direct visualization of the colon.

Colonoscopy: in-clinic test

A colonoscopy is an exam of the rectum and the colon with a slender flexible tube and camera. It is considered the gold standard for colon cancer screening because it is diagnostic and therapeutic. During the colonoscopy, your doctor can find polyps and cancers, but he or she can also remove them. This test is done every 10 years if you are at average risk of developing cancer and no polyps are found during the exam. Your doctor may recommend more frequent screening if polyps are discovered or you have risk factors.

Flexible Sigmoidoscopy: in-clinic test

A flexible sigmoidoscopy is similar to a colonoscopy, but the exam evaluates only the lower part of the colon. This test is done every five years.

CT Colonography: in-clinic test

Computer tomography (CT) colonography uses X-rays and computers to view the entire colon. This test is done every five years.

Guaiac-based fecal occult blood test (gFOBT): at-home test

The gFOBT test uses a chemical testing solution called guaiac to detect blood in the stool. It should be done once a year.

Fecal immunochemical test (FIT): at-home test

The FIT test uses antibodies to detect blood in the stool. It should be done once a year.

FIT-DNA test: at-home test

The FIT-DNA test works like the FIT test in that it uses antibodies to detect blood in the stool, but it can also detect changes in DNA (that are associated with cancer) in the stool. This test should be done every one or three years. The FIT-DNA test is also known as the Cologuard® test.

How accurate are at-home colon cancer screenings?

The at-home tests all evaluate the stool for changes that could indicate polyps or cancer. Blood in the stool can be an early symptom for polyps. These tests are obtained as a prescription from your primary care provider. You send in the results for evaluation.

The U.S. Preventive Services Task Force (USPSTF) is an independent organization of national experts that is responsible for recommending colon cancer screening guidelines. According to the USPSTF, randomized clinical trials have found stool-based at-home tests to be acceptable screening options. If results for any of these tests are positive, a follow-up colonoscopy is the next step.3 

FIT tests are more sensitive than gFOBT tests for detecting cancer. FIT-DNA tests are more sensitive than FIT alone, but less specific, which means the FIT-DNA test has a higher number of false-positive results.

What option should you choose?

For a person of average risk for colon cancer, there is no right or wrong option for which test to choose, Dr. Ludwig said. The important part is to get screened.

“Even if you are adverse to colonoscopies, you have many options,” Dr. Ludwig said. “You should discuss what works best for you with your primary care provider.”

When you consider your options, take into account your risk for colon cancer, your preference as well as your insurance coverage. Eligible people are covered by their insurance for colon cancer screening — no matter what type of test they choose. Check with your insurance company to find out what you should expect to pay.

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on April 4, 2019 - 1:19 pm

How/Where do I get at home Colonoscopy tests?

on April 4, 2019 - 3:42 pm

Hi, stewart stuesser – We recommend talking with your primary care provider about this. If an at-home colon cancer test is right for you, he or she will give you a prescription. Thanks for asking.