Beyond colonoscopy: What to know about alternative colon cancer screenings


by Rajesh Shah, MD

Mar 18, 2022

Have you been putting off screening for colon cancer? According to the Centers for Disease Control and Prevention (CDC), about 30% of adults aren’t up to date on their recommended screenings.

But, if you’re hesitant to get a colonoscopy, that doesn’t mean you should avoid screening altogether. There are other procedures and tests that may help detect colon cancer, too.

In recent years, the recommended age to start screening went down for average-risk individuals. The American Cancer Society now recommends regular screening starting at age 45 instead of 50 for people at average risk. If you’re 45 or older and haven’t been screened, it’s time to talk to your doctor about your options.  

The two main groups of screenings include procedure-based tests that provide a direct view of the colon and indirect tests that use labs or imaging to look for cancer. Here, we’ll review some of the many colon cancer screenings available today, including their advantages and disadvantages.

Procedure-based, direct colon cancer screening


Colonoscopy is probably the most well-known screening test for colon cancer. It remains the “gold standard” due to its sensitivity in finding both cancer and pre-cancerous polyps, as well as its ability to identify them accurately. It’s also the only test that is preventive. We can detect small polyps and remove them at the same time. If you’re not sure what to expect during a colonoscopy, read our colonoscopy guide for more information.

Advantages include:

  • Only needed every 10 years for those at average risk
  • Gives your doctor a direct view of the entire colon
  • Highly accurate at finding cancer and pre-cancerous polyps
  • Can prevent colon cancer by removing polyps during the same procedure

Disadvantages include:

  • Requires a special diet and bowel prep before the procedure
  • Requires time off work
  • Performed under sedation
  • Comes with small risks when compared to other indirect tests

Flexible sigmoidoscopy

This less-common procedure is like a mini-colonoscopy that examines the last third of the colon. It’s recommended every five years or every 10 years if used together with a stool-based test. It can be done without sedation but still requires bowel prep the day before. Because it doesn’t examine the entire colon, this isn’t the preferred screening for most people.

Stool-based, indirect colon cancer screening

Fecal immunochemical test (FIT)

A FIT test is the most recommended stool-based colon cancer screening method. You can collect a stool sample at home and send it in for testing. The test then looks for small amounts of blood in the stool that may indicate either cancer or a polyp.

Advantages include:

  • Easy to perform at home
  • Does not require time off work
  • No risks like those associated with a procedure
  • Less expensive for those without insurance coverage

Disadvantages include:

  • Have to do it every year
  • Not as sensitive as colonoscopy at detecting cancer
  • Not as useful for preventing cancer since small polyps may go undetected
  • May still need a colonoscopy if positive

FIT plus DNA test

This test takes FIT testing and adds a layer of genetic testing. It’s done every three years. In addition to blood, the test looks for abnormal DNA from polyps or cancer cells in the stool. The main disadvantage of the test is the potential for false positives. It also has a slightly higher cost than FIT for those without insurance.

CT colonography

Sometimes called a virtual colonoscopy, this test uses a CT scan to examine the colon and is recommended every five years. The procedure does not require sedation and comes with slightly less risk than a colonoscopy. However, like colonoscopy and flexible sigmoidoscopy, bowel prep to clear out the colon is still required.

Additional indirect tests

There are other, less widely used colon cancer screening tests. However, many of them are not as sensitive or specific in detecting cancer. For example, blood tests can look for markers in the blood that may indicate colon cancer, but the tests may not be covered by insurance. Options like colon capsule endoscopy, which uses a small pill camera, also aren’t widely used.

When to consider alternatives to colonoscopy

It’s important to note that alternatives to colonoscopy aren’t for everyone. If you have a family history of colon cancer, a history of polyps from a previous screening, certain genetic syndromes or certain medical conditions like inflammatory bowel disease, you still need a colonoscopy—and the age and timing of your screening may be different.

However, if you are at average risk and you’ve been putting off colonoscopy, talking to your doctor about alternatives might be a good first step. Both colonoscopy and FIT are considered the top options to help detect colon cancer.

The key is to have the conversation and get a screening for this highly detectable condition. When it comes to protecting yourself against colon cancer, some type of screening is better than none.   

Learn more about colon cancer and talk to your doctor today about what screening option is best for you.

About the Author

Rajesh Shah, MD, is a gastroenterologist on the medical staff at Baylor Scott & White Clinic – Buda Medical Center and Baylor Scott & White Medical Center – Austin. His clinical interests include inflammatory bowel disease, colorectal cancer screening, chronic diarrhea, gastroesophageal reflux disease and fatty liver disease. Schedule an appointment with Dr. Shah today.

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