No one disputes the value of colonoscopies for screening for colon cancer, but a recent National Cancer Institute (NCI) report discovered that some doctors may be recommending follow-up colonoscopies when they are not warranted.

And this hypervigilance may be preventing some people from getting initial colonoscopies, while requiring others to undergo an unnecessary invasive follow-up procedure, say researchers.

Reasons For Low Screening Rates

"Only 40% of people over [age] 50 have had any form of screening for colon cancer, compared to 70% to 80% for breast and prostate cancers. We were very interested in why so few were being screened," says Dr. Pauline A. Mysliwiec, an associate professor of gastroenterology at the University of California, Davis School of Medicine, who was lead investigator in the study.

Dr. Vincent Yang, director of the Division of Digestive Diseases at Emory University School of Medicine, suggests another reason for low rates of initial screening-many people are reluctant to undergo a procedure that requires fasting the day before and a mild anesthesia during the procedure.

The Study

Mysliwiec's study found that nearly half of the approximately 600 gastroenterologists and surgeons that were surveyed went beyond the recommended medical guidelines in performing follow-up colonoscopies.

The most common non-cancerous polyps found in colonoscopies are hyperplastic polyps, which most research shows do not become cancerous, and small adenomas, which are considered precancerous.

The most recent American Gastroenterological Association (AGA) guidelines call for no treatment for hyperplastic polyps. In addition, they recommend a follow-up colonoscopy five years after finding a small adenoma in otherwise low-risk patients.


However, Mysliwiec and her team found that 24% of the gastroenterologists and 54% of the surgeons surveyed recommended follow-up colonoscopies for hyperplastic polyps.

In addition, more than half of all the doctors recommended follow-up colonoscopies every three years or sooner for small adenomas.


A better-safe-than-sorry attitude" may also be a contributing factor in unnecessary followup procedures, Mysliwiec adds.

"Some people and providers are erring on the side of being more aggressive, but you are subjecting yourself to an invasive procedure that is not without risk," he says.

"If your physician recommends having another colonoscopy in a time period of less than three years, ask why," advises Mysliwiec.

What Is a Colonoscopy?

A colonoscopy allows a physician to use a scope to look inside the entire large intestine, from the lowest part—the rectum—all the way up through the colon to the lower end of the small intestine.

The procedure is used to check for early signs of cancer in the colon and rectum.

For people over age 50 who are at average risk for colon cancer, colonoscopies are recommended every 10 years.

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