Colorectal Cancer Screening

According to The American Cancer Society (ACS), thanks to improvements in prevention, early detection, and treatment, more than a million people in the United States count themselves as survivors of colon or rectum cancer (also called colorectal cancer).  With March being National Colorectal Cancer Awareness Month, we thought we would address the important topic of preventative screening.

Screening is the process of looking for cancer or pre-cancer in people who have no symptoms of the disease. Regular colorectal cancer screening is one of the most powerful weapons against colorectal cancer. Overall, the lifetime risk for developing colorectal cancer is a little less than 1 in 20 (5%). This risk is slightly lower for women than for men.

The death rate (the number of deaths per 100,000 people per year) of colorectal cancer has been dropping for several decades. One reason for this is that today, colorectal polyps are more often found by screening and removed before they can develop into cancers.

It can take as many as 10 to 15 years for a polyp to develop into colorectal cancer. Regular screening can prevent many cases of colorectal cancer altogether by finding and removing certain types of polyps before they have the chance to turn into cancer. Screening can also help find colorectal cancer early, when it’s small, hasn’t spread, and is easier to treat.

When colorectal cancer is found at an early stage before it has spread, the 5-year relative survival rate is about 90%. But only about 4 out of 10 colorectal cancers are found at this early stage. When cancer has spread outside the colon or rectum, survival rates are lower.

Unfortunately, only a little more than half of people who should get tested for colorectal cancer get the tests that they should. This may be due to things like lack of public and health care provider awareness of screening options, costs, and health insurance coverage issues.

Starting at age 50, men and women at average risk for developing colorectal cancer should use one of these screening tests below:

Tests that find polyps and cancer

  • Flexible sigmoidoscopy every 5 years*
  • Colonoscopy every 10 years
  • Double-contrast barium enema every 5 years*
  • CT colonography (virtual colonoscopy) every 5 years*

Tests that mainly find cancer

  • Guaiac-based fecal occult blood test (gFOBT) every year*
  • Fecal immunochemical test (FIT) every year*
  • Stool DNA test every 3 years*

*Colonoscopy should be done if test results are positive.

If you are at an increased or high risk of colorectal cancer, you might need to start colorectal cancer screening before age 50 and/or be screened more often. The following conditions make your risk higher than average:

  • A personal history of colorectal cancer or adenomatous polyps
  • A personal history of inflammatory bowel disease (ulcerative colitis or Crohn’s disease)
  • A strong family history of colorectal cancer or polyps
  • A known family history of a hereditary colorectal cancer syndrome such as familial adenomatous polyposis or Lynch syndrome