WASHINGTON — Postpolypectomy surveillance should follow surgery far sooner than current guidelines recommend, according to a study presented at the annual Digestive Disease Week.
In a retrospective cohort study, Dr. Madhavi Rudraraju of the University of Oklahoma, Oklahoma City, and her colleagues including Dr. William Tierney found that the recurrence rate for advanced adenomas following polypectomy was 25.8%, and the time to recurrence was 6.4 months—much sooner than the 3-year follow-up surveillance period recommended by current guidelines (Gastroenterology 2006;130:1872–85).
The researchers analyzed medical records at the VA Medical Center in Oklahoma City from Jan. 1, 1990, to Dec. 31, 2002. The patients had had at least one surveillance colonoscopy following removal of a polyp with high-grade dysplasia (HGD). Patients under 40 years of age and those with a history of colon cancer were excluded.
There were two control groups: patients with tubular adenomatous polyps, who were matched for polyp size and had at least one surveillance colonoscopy; and those with normal colonoscopy findings who had undergone at least one subsequent colonoscopy. Both groups were also matched for age, gender, race, and year of index colonoscopy.
Polyps with advanced features (adenoma greater than 1 cm; villous histology; HGD; colon cancer) were counted as outcomes of interest. Polyps found in the same region of the colon within 6 months or after documented incomplete polypectomy were counted as residual, rather than incident, lesions, and were excluded.
Most of the patients in all three groups were male and white, and had a mean age of 66 years. A total of 89 patients met the study criteria for having HGD.
In the HGD group, the mean polyp size was 1 cm, the mean number of polyps was 4.1, all had complete resection, and 73% were sessile. Polyp characteristics for the tubular adenoma group were similar—mean size was also 1 cm, mean number was 4.4, 79.8% were sessile, and, as in the HGD group, 100% were completely resected.
“At the Oklahoma VA Medical Center, surveillance is performed at the least at 3 and 12 months, but most patients had it at 3 months, 6 months, 9 months, and 12 months,” said Dr. Rudraraju. This practice of aggressive surveillance has continued at this facility despite the recent guidelines.
The study found that in the HGD group, 25.8% (23 of 89 patients) went on to develop advanced polyp recurrence, and among those 23 patients, the median time to recurrence was 6.4 months. In contrast, 16.8% (15 of 89) of the tubular adenoma group developed recurring advanced polyps at a median time of 36.6 months after initial polypectomy. In the group with no polyps on initial colonoscopy, 5.6% (5 of 89) developed advanced polyps at a median of 34.8 months later.
The range of advanced polyp development in the HGD group was 2.6–101 months. Overall, 5.6% (5 of 89) developed colon cancer at a median of 6 months after initial polypectomy.
“Until we have further prospective evidence about this group of patients with high-grade dysplasia, it would be very reasonable for [physicians] to consider intense early surveillance, given [that] this represents the largest study to date looking at this particular group of patients,” said Dr. Rudraraju in an interview.