Colonoscopies Can Prevent Cancer

Colonoscopies and polyp removals prevented many cancers from developing

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Colonoscopies are touted as the best way to prevent colon cancer. Now, a new study shows just how well they work.

The more non-cancerous growths physicians removed on colonoscopy, the lower the chances that patients would later develop cancer, according to California researchers.

"Discuss colonoscopy with your doctor if you are 50 years or older."

This research was led by Douglas Corley, MD, PhD, of Kaiser Permanente Division of Research in Oakland.

Dr. Corley and colleagues found that for every 1 percent increase in adenoma detection in colonoscopy, there was a 3 percent lower risk for colon cancer.

An adenoma is a type of colon polyp. Some polyps are benign, meaning they are not cancerous. However, other polyps can be cancer or can become cancer.

Colon cancer is the second leading cause of cancer deaths in the United States.

The researchers studied Kaiser Permanente patients in Northern California who had colonoscopies from January 1998 to December 2010. All patients were 50 years and older (the age at which the average person is recommended to have their first colonoscopy).

The patients were followed for anywhere from six months to 10 years to see if they developed any interval cancers (cancers detected from after colonoscopy until 10 years later, when it is recommended they have a second colonoscopy).

All the colonoscopies were performed by gastroenterologists (doctors who specialize in disorders of the digestive system) who had previously performed at least 300 colonoscopies.

For the study, 264,972 colonoscopies were performed, and 712 patients were diagnosed with colon cancer in the decade between colonoscopies. Of these diagnosed patients, 255 had advanced stage cancer and 147 died.

The researchers found that for every 1 percent increase in adenomas detected at colonoscopy, there was a 5 percent lower risk for fatal interval colorectal cancers.

Dr. Corley and team noted a few possible problems with this study, such as that some physicians may be better at removing entire adenomas than others, and bowel preparations were not assessed.

However, their finding that there was a relationship between adenoma detection and lower risk for subsequent cancer diagnoses adds more support to the recommendation for colonoscopies, they added.

Furthermore, the adenoma detection rate may be used to ensure that physicians who perform colonoscopies are doing the best they can, the researchers wrote.

“These findings support the validity of the adenoma detection rate as a quality measure of physicians’ performance of colonoscopy in community practice, and they suggest that the development and testing of interventions to improve the adenoma detection rate are warranted,” they concluded.

This study was published April 3 in The New England Journal of Medicine.

The authors did not report any conflicts of interest.

Review Date: 
April 3, 2014
Last Updated:
April 3, 2014