SAN DIEGO — Physicians may be conducting surveillance colonoscopy too often on low-risk patients and not enough on high-risk patients, according to results of a substudy of the Polyp Prevention Trial presented at the annual Digestive Disease Week.
Dr. Adeyinka Laiyemo, a cancer prevention fellow at the National Cancer Institute, said that colonoscopy resources need to be managed more effectively, based on the substudy's findings. He presented data on behalf of his colleagues at NCI and the University of Pittsburgh Cancer Institute.
The Polyp Prevention Trial was a 4-year randomized, controlled trial of a low-fat, high-fiber, fruit and vegetable diet on adenoma recurrence. The diet was not found to be effective. However, when that study ended in 2000, 1,297 subjects agreed to be followed.
Patients were followed for a mean of 6.2 years. Of the 1,297 patients, 774 (60%) had a repeat colonoscopy during the follow-up period. There were 431 patients who were considered low risk because they had one or two nonadvanced adenomas at baseline and no adenoma recurrence at the end of the Polyp Prevention Trial. Thirty percent had a repeat colonoscopy within 4 years, which is sooner than recommended.
There were 55 patients who were considered high risk because they had an advanced adenoma and/or three or more nonadvanced adenomas at baseline and at the end of the original study. Only 41% had a surveillance colonoscopy within the recommended 3 years, and 64% had a repeat exam within 5 years.
After examining the yield of these colonoscopies, the researchers determined that only 4% of the lowest risk group had significant lesions at the 6-year mark, compared to 40% of the highest risk group, said Dr. Laiyemo. “This leads us to realize that we need to improve our use of colonoscopy.”