Colonoscopy surveillance every 3 years may be sufficient after polypectomy

A multicenter randomized trial in Japan found that a single surveillance colonoscopy three years postpolypectomy and two surveillance colonoscopies at one and three years were similarly accurate for detecting clinically important neoplastic lesions.

Patients who have had a polypectomy may be able to undergo surveillance colonoscopy every three years rather than annually, according to a new study.

Researchers in Japan performed a multicenter randomized trial to determine whether detection of advanced neoplasia was sufficient with follow-up colonoscopy at three years versus at both one and three years after polypectomy. Participants at 11 facilities had two rounds of colonoscopy at baseline, performed at one-year intervals, to remove all neoplastic lesions. Those in whom invasive colorectal cancer, sessile adenomas of 30 mm or greater, or inflammatory bowel disease was detected were excluded; the remaining patients were randomly assigned to follow-up colonoscopy at one and three years (the two-examination group) or at three years only (the one-examination group). The primary outcome was incidence of advanced neoplasia (defined as lesions with low-grade dysplasia of ≥10 mm, high-grade dysplasia, or invasive cancer) at follow-up colonoscopy. The study results were published Nov. 2 by Gut.

Overall, 3,926 patients were enrolled in the study (mean age, 57.3 years; 62% men) and 2,757 underwent two-round baseline colonoscopy. Of the 2,166 patients randomly assigned to the study groups, 1,087 were assigned to receive two follow-up examinations and 1,079 were assigned to receive one. Two hundred seventeen patients in the two-examination group and 174 in the one-examination group were lost to follow-up, and 169 and 142, respectively, had follow-up colonoscopy beyond the designated study period and were excluded from the per protocol analysis. Overall, 29 advanced neoplasias were detected in 28 patients over three years of follow-up in both groups. In the per protocol analysis including 701 and 763 patients in the two-examination and one-examination groups, respectively, incidence of advanced neoplasia was 1.7% versus 2.1% (P=0.599). The noninferiority test yielded significant results (P=0.017 in the per protocol analysis and P=0.001 in the intention-to-treat analysis). Eighteen (62%) of the 29 advanced neoplasias detected were nonpolypoid colorectal neoplasms, and of these, 15 (83%) were of the laterally spreading tumor, nongranular type.

The authors noted that the study involved only a single country and that participating endoscopists were not blinded to patients' study group, among other limitations. “The present study demonstrated the equivalent accuracy of detecting clinically important neoplastic lesions with a single surveillance colonoscopy at 3 years, and two surveillance colonoscopies at 1 and 3 years postpolypectomy,” the authors wrote. “The finding indicates that it is not necessary to perform intensive surveillance colonoscopies at 1 and 3 years, and a surveillance colonoscopy at 3 years after polypectomy is sufficient.” In addition, they pointed out that the large percentage of nonpolypoid colorectal neoplasms detected as advanced neoplasia emphasized the importance of paying close attention to these types of lesions.