Colorectal Cancer Screening

Regular screening can often find colorectal cancer early, when it is most likely to be curable. In many cases, screening can also prevent colorectal cancer by finding and removing polyps (growths) before they turn into cancer.

Risk Factors for Colorectal Cancer

A risk factor is anything that increases your chance of getting a disease such as cancer, but risk factors do not tell us everything. Having one or more risk factors does not mean you will definitely get colorectal cancer, and having no risk factors does not mean you cannot get it.
Most  colorectal cancers develop from lifestyle-related factors and increasing age. About 9 out of 10 people diagnosed with colorectal cancer are at least 50 years old.

  • Personal history of colorectal polyps or colorectal cancer
  • Personal history of inflammatory bowel disease
  • Family history of colorectal cancer or adenomatous polyps
  • Personal or family history of inherited syndromes; the most common are familial adenomatous polyposis (FAP) and hereditary nonpolyposis colon cancer (also called Lynch syndrome) 

Other factors that are associated with an increased risk of colorectal cancer include:    
  • Smoking
  • Heavy alcohol use
  • High consumption of red meat
  • Diabetes mellitus
  • Sedentary lifestyles
  • Obesity


Colorectal cancer can be prevented through dietary changes, regular screenings and genetic testing.


Screening Tests for Colorectal Cancer

Polyps and early colon cancers typically do not cause any symptoms; therefore, it is important to get a screening test for early detection. Most polyps can be seen and removed during colonoscopy before they have the chance to become cancerous. Talk to your doctor to determine the best and most appropriate screening colorectal test(s) for you, as well as how often you should be screened.  Regular screening is the key to preventing colorectal cancer. 


Screening for colorectal cancer using high-sensitivity fecal occult blood testing (to detect ‘hidden’ blood or small amounts of blood not detectable by visual inspection), sigmoidoscopy or colonoscopy is generally recommended beginning at age 50 for those without specific risk factors. For those at higher risk of developing colorectal cancer, screening should begin at a younger age, and may need to take place more frequently. The decision to be screened after age 75 should be made on an individual basis, in consultation with your doctor.

Some screening tests can find polyps, benign growths and cancer.


  • Flexible sigmoidoscopy – doctors use a flexible, lighted tube (sigmoidoscope) to look at the interior walls of the rectum and part of the colon. 
  • Colonoscopy – performed with a flexible, lighted tube (colonoscope) to look at the interior walls of the rectum and the entire colon. Colonoscopies can be used as screening tests or as follow-up diagnostic tools when the results of another screening test are positive. 
  • Double-contrast barium enema (also referred to as a lower gastrointestinal or GI series) – an X-ray test that highlights the inner part of the colon and rectum. 
  • Computed tomography (CT) colonography, or virtual colonoscopy – creates a 3-D view of your colon and rectum.  

Some tests predominantly find cancer.


  • Fecal blood tests, including high-sensitivity fecal occult blood test (FOBT) – checks for hidden blood in three consecutive stool samples
  • Fecal immunochemical test (FIT) – looks for occult blood in feces and is sometimes preferred over FOBT