Should I Have a Colonoscopy, Stool Test, or Blood Test to Screen for Colorectal Cancer?

Colorectal cancer (CRC) is the third most commonly diagnosed cancer and the third leading cause of cancer-related deaths in both men and women in the U.S. Approximately 153,020 new cases of CRC are expected annually, including 12% of cases in people under age 50. Around 52,550 deaths from CRC occur each year.

 

Evaluating Your Risk

 

Patients with a higher risk of CRC include: a personal history of any colon polyps or CRC, family history of CRC, inflammatory disorders of the colon such as Crohn’s or Ulcerative Colitis, and certain genetic conditions such as Lynch Syndrome. If you are at higher risk, you will always need a colonoscopy to screen for CRC.

 

Colonoscopy

 

Colonoscopy can prevent CRC by detecting AND removing precancerous polyps. While it has some inconveniences such as taking a prep and potentially missing work, it is the best proven way to prevent colon cancer. Based on the number, size, and shape of the polyps identified, we will recommend an appropriate follow-up interval.

 

Stool Tests

 

Stool tests such as FIT or Cologuard offer a less invasive way of detecting colon cancer. While they are easy to complete, they only detect between 74-92% of CRCs and 24-42% of high risk polyps with a high likelihood of developing cancer. These tests are great at finding colon cancer, but many high risk polyps are left behind with the potential to become cancer in the near future.

 

Blood Tests

 

If you are certain you do not want to undergo a colonoscopy or complete a stool test, blood testing may be an option for you. They detect CRC at a rate of 67-79% and identify high risk polyps in less than 10% of people. This is to be used as a last resort.

 

Summary

 

Colonoscopy is by far the best way to prevent CRC as we are able to remove polyps of all sizes from the colon. Stool tests are more convenient but are not nearly as good at detecting polyps with a higher risk of developing cancer. Blood tests are far inferior to both colonoscopy and stool tests; they should only be used as a last resort.