Colon Cancer

Screening for Colon Cancer

The goal of colorectal cancer screening is to remove precancerous polyps before they develop into cancer or to diagnose a cancer in its early stages when survival is greatest. A consortium of five medical societies including surgeons and gastroenterologists, and sponsored by the United States Agency for Health Care Policy and Research, has defined separate screening protocols based on an individual's assignment to risk categories.

How often you should be screened

Recommended cancer screening strategies begin with patients who have a family history (first degree relative) of colorectal cancer, screening should begin at 40 years old or 10 years prior to the family member's age at diagnosis, whichever is earlier.
Evidence is accumulating that colonoscopy may be especially beneficial in screening beginning at age 40 in black males. Epidemiological studies suggest that Black males are 10 percent more likely then white males to be diagnosed with colorectal cancer, and may be two times more likely to develop cancer prior to age 50.
In individuals without symptoms or increased risk factors colorectal cancer screening should begin at 50 years old.
If no precancerous polyps are found, screening will occur every 10 years.
If precancerous polyps are found, screening will be more frequent, typically every 3 to 5 years.
Yearly testing for blood in the stool with cards
Flexible sigmoidoscopy (which only examines the rectum and lower colon) every 3 to 5 years
Barium enema every 5 years

Testing Methods

Colonoscopy

The use of colonoscopy is the superior alternative among testing options. Colonoscopy screens for cancer by examining the whole colon, and is a tool to prevent cancer by removing pre-cancerous colorectal polyps (polypectomy). For more information on colonoscopy including preparation and what you can expect from the test, please see the related NetWellness orginal feature.

Virutal Colonoscopy

At this time, there are not enough data to recommend CT scanning otherwise known as virtual colonoscopy. Virtual colonoscopy requires the patient to take the same oral laxative as an endoscopic colonoscopy. The colon is inflated with air through a tube in the rectum, and the patient has to undergo a CT scan. This procedure does not allow for polyp removal and can miss smaller polyps detected by endoscopic colonoscopy. Another reason to avoid "virtual colonoscopy" is that colon cancer can recur, even at a different location in the colon.

Follow up

If the entire colon was not visualized by colonoscopy prior to surgery, a colonoscopy will need to be performed within six months after surgery. Assuming this does not reveal another cancer, or the first colonoscopy was complete, it is recommended that:

Patients have a colonoscopy one to three years after surgery to detect new polyps or tumors.
CEA monitoring is also recommended in follow-up.
Office visits at least three times a year for the first two years are recommended because symptoms are often the first indicator of cancer recurrence.

Support

There are many excellent support groups and references that the patient's physician will be happy to share. The following websites can provide further information:

American Cancer Society - www.cancer.org/
National Cancer Institute - www.cancer.gov/
American College of Gastroenterology - www.acg.gi.org/
American Gastroenterological Association - www.gastro.org/
American Society of Colon and Rectal Surgeons - www.fascrs.org/

The American Cancer Society can address cancer-related questions 24 hours a day at 1-800-ACS-2345. Concerns should also be addressed with a physician.

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Last Reviewed: Feb 18, 2008

Gregory S Cooper, MD
Professor
Ireland Cancer Center
Gastroenterology Division
University Hospitals
School of Medicine
Case Western Reserve University

Timothy O'Brien, MD
Director and Associate Professor
Cancer Care Center
MetroHealth Medical Center
School of Medicine
Case Western Reserve University