Risk of recurrent advanced colorectal neoplasia in individuals with baseline non-advanced neoplasia followed up at 5 vs 7-10 years

Background and Aim: Colorectal cancer (CRC) is one of the commonest cancers, especially among the Asian populations. We compared the recurrence rate of advanced colorectal neoplasia (ACN) at 5 year vs 7-10 years among individuals with non-advanced adenoma (NAA) detected and polypectomized at baseline colonoscopy in a large Chinese population.Methods: We extracted data of a large Chinese population with NAA polypectomized who received surveillance colonoscopy after 5 or 7-10 years from a large database (2008-2018). The outcome variable included recurrence of ACN at surveillance colonoscopy. We examined the association between length of surveillance and the outcome variable, whilst controlling for risk factors of colorectal cancer.Results: We include 109 768 subjects who have received a baseline colonoscopy from our dataset. They were aged 67.35 (SD 9.84) years, and 60.9% of them were male subjects. The crude 5-year and 10-year recurrence rate of ACN was 1.50% and 2.42%, respectively (crude odds ratio = 1.629, 95% CI 1.362 to 1.949, P < 0.001). From the binary logistic regression model, individuals with surveillance colonoscopy performed at 10 years had a statistically higher recurrence rate of ACN than those followed-up at 5 year (adjusted odds ratio [aOR] = 1.544, 95% CI 1.266 to 1.877, P < 0.001), but the effect size of aOR is small.Conclusions: There is a small difference in recurrence of ACN between individuals who received colonoscopy workup at 5 years vs 7-10 years. These findings support a 7-10 years surveillance period after baseline NAA was polypectomized.