Colorectal adenoma recurrence rates among post-polypectomy patients in the placebo-controlled groups of randomized clinical trials: a meta-analysis

BACKGROUND: Evidence regarding the benefit of therapy to prevent the post-polypectomy recurrence of colorectal adenoma is limited. Endoscopic recurrence is the main outcome according to an evaluation of trials involving recurrence prevention. AIM: To estimate the recurrence rates of post-polypectomy colorectal adenoma in placebo-controlled arms of randomized clinical trials and to identify the prognostic factors influencing these rates. METHODS: We combined data from all randomized controlled trials evaluating therapies for colorectal adenoma using placebo from 1988 to 2016. The data were combined in a random-effects model. Primary outcomes were endoscopic adenoma and advanced adenoma recurrence of colorectal adenoma. RESULTS: The pooled estimates of the adenoma recurrence rates were 37% (95% confidence interval [CI], 33%-41%; range, 33%-52%) at 1 year, 47% (95% CI, 41%-54%; range, 46%-51%) at 2 years, 41% (95% CI, 33%-48%; range, 20%-61%) at 3 years, 48% (95% CI, 38%-57%; range, 37%-53%) at 4 years, and 60% (95% CI, 52%-68%; range, 48%-68%) at 5 years. The pooled estimates of the advanced adenoma recurrence rates were 10% (95% CI, 6%-15%; range, 7%-13%) at 1 year, 12% (95% CI, 8%-16%; range, 3%-19%) at 3 years, 14% (95% CI, 10%-18%; range, 13%-16%) at 4 years, and 14% (95% CI, 10%-19%; range, 9%-21%) at 5 years. Significant heterogeneity among the randomized clinical trials (P < 0.001) was observed for each recurrence rate. CONCLUSIONS: This meta-analysis confirms the heterogeneity of recurrence rates among post-polypectomy colorectal adenoma patients who received placebo. No single design variable was identified that might explain the heterogeneity.