Colorectal Cancer Overview

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Early Detection, Diagnosis, and Staging TOPICS

Can colorectal cancer be found early?

Screening is the best way to find colorectal cancer early, because it looks for cancer in people who do not have any symptoms. In many cases, these tests can find colorectal cancers at an early stage and greatly improve treatment outcomes. Screening tests can also help prevent some colorectal cancers by allowing doctors to find and remove polyps that might go on to become cancer. Screening tests for colorectal cancer include:

  • Fecal occult blood test (FOBT) and fecal immunochemical test (FIT): Samples of stool (feces) are checked for blood, which might be a sign of a polyp or cancer.
  • Sigmoidoscopy: A flexible, lighted tube is put into the rectum and lower colon to check for polyps and cancer.
  • Colonoscopy: A longer, flexible tube is used to look at the entire colon and rectum.
  • Double contrast barium enema: This is an x-ray test of the colon and rectum.
  • CT colonography (virtual colonoscopy): This is a type of CT scan of the colon and rectum.

FOBT and FIT mainly find cancer, but can find some polyps.

Sigmoidoscopy, colonoscopy, double-contrast barium enema, and CT colonography are good at finding cancer and polyps. Polyps found before they become cancer can be removed, so these tests may prevent colorectal cancer. This is why these tests are preferred if they are available and you are willing to have them.

For more details about using these tests to screen for colorectal polyps and cancer, please see Colorectal Cancer Prevention and Early Detection.


Last Medical Review: 10/15/2014
Last Revised: 10/24/2014