Number of Adenomas Strongest Predictor for Advanced Neoplasia

October 19, 2007 (Philadelphia) — The presence of 3 or more adenomas is the strongest predictor for identifying individuals with advanced neoplasias and high-recurrence risk status on follow-up colonoscopy, a study presented here has found.
Carol Burke, MD, director of the Center for Polyps and Cancer at the Cleveland Clinic in Ohio, described data from the study during a session at the American College of Gastroenterology 2007 Annual Scientific Meeting. The study aimed to determine which factors can predict recurrent advanced neoplasia or can be classified as a high recurrence risk at follow-up colonoscopy.
The study included 800 subjects, drawn from 3 postpolypectomy chemoprevention trials dating back to 1984, who had at least 1 baseline adenoma and who had undergone complete polypectomy. Subjects had to have a 3-year follow-up postpolypectomy colonoscopy, and individuals who had colorectal cancer on the baseline examination were excluded. Mean age at the time of randomization was 60 years, and the mean time of follow-up colonoscopy was 37 months.
Subjects were categorized as low risk or high risk for the recurrence of advanced neoplasia based on Multi-Society Task Force criteria, which recommend different surveillance intervals based on adenoma features: 5 to 10 years for individuals with low recurrence risk (<> 2 adenomas, ≥ 10 mm). Advanced neoplasia was defined as adenoma larger than 9 mm.
A multivariate regression analysis was used to obtain risk ratios (RRs) for the outcomes on the basis of baseline adenoma characteristics and the subjects' risk group.
The study found that high-risk status at baseline was significantly associated with recurrent advanced neoplasia (RR, 1.9; 95% confidence interval [CI], 1.2 - 3.0; P = .01) and high-risk status on follow-up colonoscopy (RR, 2.1; 95% CI, 1.5 - 3.1; P < .0001). Adenoma multiplicity was associated with both outcomes, but pathology was not associated with either outcome, and large size was only associated with advanced neoplasia.
"Individuals with advanced adenoma at baseline were twice as likely as individuals with a nonadvanced adenoma to have a follow-up advanced neoplasm," Dr. Burke told attendees. Sex, race, or family history of colorectal cancer did not predict an advanced neoplasm or a high-risk status, she added.
"The implication is that we all, when doing colonoscopies, should be diligent in efforts to detect synchronous neoplasia" to recommend the proper postpolypectomy interval, Dr. Burke concluded.
Commenting on the findings, Amy Foxx-Orenstein, MD, president of the American College of Gastroenterology and an associate professor of medicine at the Mayo Clinic in Rochester, Minnesota, said, "The interesting thing is that the number of polyps appears to be the issue. We need to have screening tools that allow us to identify those polyps maximally."
However, this raises a question about computed tomography (CT) colonography, said Dr. Foxx-Orenstein, who moderated the session. Although recent data have suggested that CT colonography is very good at identifying larger lesions, "the smaller lesions may be missed," she said. "And if it's the number of polyps that you're actually looking at, does that therefore raise an issue as to how valuable that tool might be or what we might be missing?"
Drs. Burke and Foxx-Orenstein have disclosed no relevant financial relationships.
American College of Gastroenterology 2007 Annual Scientific Meeting: Abstract 9. Presented October 15, 2007.