Randomized Comparison of Surveillance Intervals after Colonoscopic Removal of Newly Diagnosed Adenomatous Polyps

Abstract

Background: The identification and removal of adenomatous polyps and post-polypectomy surveillance are considered to be important for the control of colorectal cancer. In current practice, the intervals between colonoscopies after polypectomy are variable, often a year long, and not based on data from randomized clinical trials. We sought to determine whether follow-up colonoscopy at three years would detect important colonic lesions as well as follow-up colonoscopy at both one and three years. Methods: Patients were eligible if they had one or more adenomas, no previous polypectomy, and a complete colonoscopy and if all their polyps had been removed. They were randomly assigned to have follow-up colonoscopy at one and three years or at three years only. The two study end points were the detection of any adenoma, and the detection of adenomas with advanced pathological features (defined as those >1 cm in diameter and those with high-grade dysplasia or invasive cancer). Results: Of 2632 eligible patients, 1418 were randomly assigned to the two follow-up groups, 699 to the two-examination group and 719 to the one-examination group. The percentage of patients with adenomas in the group examined at one and three years was 41.7 percent, as compared with 32.0 percent in the group examined at three years (P = 0.006). The percentage of patients with adenomas with advanced pathological features was the same in both groups (3.3 percent). Conclusions: Colonoscopy performed three years after colonoscopic removal of adenomatous polyps detects important colonic lesions as effectively as follow-up colonoscopy after both one and three years. An interval of at least three years is recommended before follow-up examination after colonoscopic removal of newly diagnosed adenomatous polyps. Adoption of this recommendation nationally should reduce the cost of post-polypectomy surveillance and screening., Adenomatous polyps have been identified with increasing frequency in recent years as a result of the introduction of screening with tests of stool for occult blood and flexible-instrument sigmoidoscopy and wider use of colonoscopy, colonoscopic polypectomy, and double-contrast barium enemas. It is widely held that adenomatous polyps are precursors of colorectal cancer and that their removal is important because of its potential for reducing the incidence and mortality of colorectal cancer1–5. These concepts have formed the basis for the removal of adenomatous polyps on detection and for the implementation of follow-up surveillance programs6–10. Periodic surveillance examinations… © 1993, Massachusetts Medical Society. All rights reserved.