Colonoscopy After Polyp Removal

Dr. Timothy Hoops
Last Modified: November 1, 2001

Dear OncoLink "Ask the Experts,"
My father underwent a colonoscopy at age 70. Polyps were removed. How often should he have a colonoscopy?  
Thank you,

Dr. Timothy Hoops, Clinical Assistant Professor of Medicine in the Gastroenterology Division at the University of Pennsylvania and Director of Gastroenterology at Penn Medicine at Radnor, responds:

Dear CG,
In the early 90's, a study was done in which about 1500 patients who had undergone polypectomies were divided randomly into two groups. One group had follow-up colonoscopies at 1 year and at 3 years. The other group had a repeat colonoscopy at three years only. That study demonstrated that there was no difference between the two groups in the number of recurrent polyps or cancers found. This changed the practice of gastroenterology from yearly follow-up colonoscopies, which had been the standard, to every three years.

The same researchers have shown that if there were less than three polyps and they were very small, it was probably safe to even wait five years for the next procedure. This data supports what is known about the biology of the development of cancer. In most, if not all cases cancers develop from adenomatous polyps. The process of going from normal tissue to polyp to cancer is quite long extending from 10 to 15 years and possibly even longer. Thus, the longer intervals between colonscopies after removal of a polyp is safe and reduces the discomfort and small risk associated with these procedures.

It may benefit your father to have a colonoscopy no sooner than 3 years unless there was some specific finding that warranted an earlier procedure.