• What is colon (colorectal) cancer?
• Screening tests for colon (colorectal) cancer
• Colon Cancer Screening Recommendations
• Related Links and Videos
• Cancer Screening for other Cancers

What is colon (colorectal) cancer?

Colon cancer begins in the colon's innermost lining, targeting cells that produce mucus and other fluids. These cells can form a colon polyp when they undergo mutations or changes. Over time, some of these polyps may develop into cancer, a process that typically takes about 10 years. If colon cancer is not detected and treated, it can progress through the layers of tissue and muscle surrounding the colon and eventually reach the outer layer. Additionally, colon cancer can spread to other areas of the body through lymph nodes or blood vessels.

Screening tests for colon (colorectal) cancer

Four tests commonly utilized for screening are outlined below.

Fecal occult blood testing - A fecal occult blood test checks for hidden blood in stool samples.

Fecal immunochemical testing - A fecal immunochemical test is a safe and painless at-home test that screens for blood in stool.

Flexible Sigmoidoscopy - A flexible sigmoidoscopy is a procedure to examine the inside of your lower large intestine. A healthcare provider looks inside with a long, flexible, tube-lighted camera on the end. A flexible sigmoidoscope goes through your anus and rectum to examine the lower third of your colon.

Colonoscopy - A sigmoidoscopy examines the lower part of the colon, while a colonoscopy inspects the entire colon. Both use a camera-equipped tube, but a colonoscopy is more comprehensive and often requires more preparation, as well as possible sedation or anesthesia.

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A sigmoidoscopy, left, examines only the lower part of the colon (sigmoid colon), while a colonoscopy, right, examines the entire length of the colon.