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Is it Time? Colon Cancer Screening

Many testing options available

Many adults have missed regular screenings this year due to limited in-person visits with doctors. One disease that regular screenings can catch early is colorectal cancer or colon cancer. If you’re turning 50 or have a family history of the disease, getting screened regularly can save your life. When it’s your time to get screened, you may want to know how screenings work or which options are available to you.

It’s easy to ask friends about their experiences or note commercials about home testing kits. However, your best bet is to talk to your doctor about getting screened. The CDC describes these common options:

Stool Tests

  • Guaiac-based fecal occult blood test (gFOBT) uses the chemical guaiac to detect blood in the stool. It’s done once a year. You’ll receive a test kit from your doctor. You’ll obtain a small amount of stool at home and then return the test kit to your doctor.

  • Fecal immunochemical test (FIT) uses antibodies to detect blood in the stool. It’s done once a year in the same way as a gFOBT.

  • FIT-DNA test (also referred to as the stool DNA test) combines the FIT with a test that detects altered DNA in the stool. You’ll collect an entire bowel movement and send it to a lab. It’ll be checked for cancer. It’s done once every three years.

Flexible Sigmoidoscopy

During a flexible sigmoidoscopy exam, your doctor will put a short, thin, flexible, lighted tube into your rectum. The doctor checks for polyps or cancer inside the rectum and lower third of the colon. It should be done every 5 years, or every 10 years, based on your doctor’s recommendation, with a FIT every year.


A colonoscopy is similar to a flexible sigmoidoscopy. The doctor uses a long, thin, flexible, lighted tube to check for polyps or cancer inside the rectum and the entire colon. Your doctor can find and remove most polyps and some cancers. Colonoscopies are used as a follow-up test if anything unusual is found during one of the other screening tests. It should be done every 10 years (for people who do not have an increased risk of colorectal cancer).

CT Colonography (Virtual Colonoscopy)

Computed tomography (CT) colonography, also called a virtual colonoscopy, uses X-rays and computers to produce images of the entire colon, displayed on a computer screen for the doctor to analyze. If you’re at average risk, this screening should be done every 5 years.

Each test has its strong points, depending on your situation. Use Secure Messaging (sign in required) to discuss your test with your doctor and learn how often you might need to be tested. Keep in mind that which test your provider chooses for you depends on:

  • Your preferences.

  • Your medical condition

  • The likelihood that you will get the test.

  • The resources are available for testing and follow-up.

Please vote in our unscientific poll. All responses are anonymous.

Do you know if you have a family history of colon cancer?

Read More

Five Questions about Checking for Colon Cancer

Colorectal Cancer Screening (Veterans Health Library)

Colonoscopy (Veterans Health Library)

Updated March 23, 2021