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, multicenter, 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 prospectively. The aim was to determine utilization and yield of surveillance colonoscopy in the community, said Dr. Laiyemo, who briefed reporters.
Most studies of surveillance have been based on physician surveys, generally asking them about hypothetical cases, he said. This study followed the actual use of colonoscopy, as reported by patients and through medical record reviews.
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. This is sooner than recommended, Dr. Laiyemo said.
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 with 40% of the highest risk group, Dr. Laiyemo said. “This leads us to realize that we need to improve our use of colonoscopy resources,” he said.
Dr. Laiyemo made no conflict-of-interest disclosures.