Early Detection of Colorectal Cancer

Early Detection of Colorectal Cancer

Colorectal cancer may not cause any signs or symptoms until the disease is advanced. That’s why it’s important to be screened for colorectal cancer regularly. Screening tests allow doctors to spot cancer in the colon or rectum at an early stage, when it’s easier to cure. Screenings also help prevent cancer by finding polyps so they can be removed before they become cancerous. 


The American Cancer Society (ACS) recommends colorectal cancer screenings beginning at age 50 for people who have no known risk factors other than age. The frequency depends on the screening method.

If you have a family history of colorectal cancer or you have other risk factors for colorectal cancer, talk to your doctor about starting screenings earlier in life—and maybe being screened more often.

The main screening tests include:

  • Fecal occult blood test to detect any blood in your stool (which could be caused by cancer or by other some other condition)
  • Flexible sigmoidoscopy, in which the doctor examines your rectum and the lower part of your colon for polyps or tumors using a flexible, lighted tube
  • Colonoscopy, which allows your doctor to see your entire colon and rectum

If your doctor finds something abnormal during a screening, your doctor will remove samples of tissue (and maybe whole polyps) to be checked under a microscope for cancer cells (a biopsy).

Screening Innovations

New tests for colorectal cancer screening are being studied. For example, virtual colonoscopy (also called computed tomographic colonography, or CT colonography) uses special X-ray equipment to take pictures of the colon. A computer then assembles these pictures into detailed images that show polyps and other abnormalities.

Virtual colonoscopy may cause less discomfort and take less time than conventional colonoscopy. It is less invasive, and patients do not need sedating medication, like they do with conventional colonoscopy. However, doctors cannot do biopsies or remove polyps during virtual colonoscopies, as they can during conventional colonoscopies. A virtual colonoscopy requires the same preparation as a conventional colonoscopy.

In the News

Watch colon cancer survivor Anita Mitchell and SCCA's Samuel H. Whiting, MD, PhD on KING-5 TV enter the giant colon for Colon Cancer Awareness Month.