Screening for Colon Cancer: Your questions answered

Colorectal cancer (CRC) – cancer that starts in the colon or rectum – is the fourth most common cancer in adults and the second leading cause of cancer deaths in the US. The disease takes ten to fifteen years to develop and risk for the disease increases as you get.

When should I get screened?

On Wednesday the 30th of May 2018, updated guidelines for colorectal cancer screening in average-risk adults were published by the American Cancer Society (ACS) in CA: A Cancer Journal for Clinicians. The new recommendation is that adults aged 45 years and older with an average risk of colorectal cancer undergo regular screening.

The United States Preventative Services Task Force (USPFTF), a panel of experts in prevention and evidence-based medicine, recommends that individuals with average risk of colon cancer should start screening from the age of 50.

Who should consider screening before the age of 45?

Individuals with a family history of colon cancer, that is, one first degree relative with early onset (under 50) of colon cancer or multiple first degree relatives with the disease, should get screened earlier. Speak to your doctor if this applies to you.

How should I be screened for colon cancer?

There are a few different methods of screening for colon cancer, each with its own set of risks and benefits. All screening tests fall into one of the following categories:

  • Stool-based tests, which test your faecal matter for the presence of blood.
  • Direct visualisation tests, such as a colonoscopy, where a camera is inserted into your colon.

Here is a table summarising all available tests, the recommended frequency for conducting these tests, and any additional notes on each test:

Screening test
What is this?
Stool-based tests
A laboratory test that is performed on your stool sample (usually collected in a plastic jar). There are special dietary requirements to follow before you give the sample.
This test is also performed in a laboratory but there are collection kits available, like UDoColonTest, that don’t entail handling of faeces. There are no dietary requirements or special preparations, which is one reason this test has largely replaced gFOBT. The other major reason for this is that FIT is more sensitive than gFOBT.
Every 1 to 3 years
This is a new test and longitudinal studies are still being done.
Direct visualisation tests
Every 10 years
This is the gold standard. Even when it’s not used as a primary screening method, it is conducted in follow up investigations. However, there are potential harms associated with colonoscopy, such as bleeding or infection.
Flexible sigmoidoscopy
Every 5 years
This test is rarely done.

Where do I start?

Discuss your risks for Colon Cancer with your doctor, and be sure to ask for a summary of all available screening methods before deciding what’s right for you. For more information on UDoColonTest, a screening test that you can do at home without making a doctor’s appointment, click here.