A delay in colonoscopy after positive fecal tests leads to higher incidence of colorectal cancer: A systematic review and meta-analysis

Background and Aim: A delay in performing colonoscopies after positive fecal tests in a screening program may risk neoplastic progression. Our objective is to conduct a systematic review and meta-analysis to evaluate the effects of timing of a colonoscopy after a positive fecal test on the detection of colorectal cancer. Methods: Cochrane guidelines and PRISMA statement were followed for this review. Digital dissertation databases were searched from inception to June 1, 2020, and all studies reporting the detection rates of colorectal cancer on the basis of different time intervals between a positive fecal test and the post-test colonoscopy were included. We compared the detection rates of colorectal cancer (overall and advanced-stage) and advanced adenoma based on different time intervals. Results: A total of 361 637 patients from six observational studies were included for the analysis. The odds of detecting any colorectal cancer (odds ratio [OR] 1.58, 95% confidence interval [CI] 1.23-2.03, P < 0.001), advanced-stage colorectal cancer (OR 2.16, 95% CI 1.47-3.16, P < 0.001), or advanced adenomas (OR 1.17, 95% CI 1.06-1.28, P = 0.001) are significantly higher if the colonoscopies are performed after 6 months from a positive fecal test, compared with within 6 months. There was no significant difference in the detection rates based on a 1-month, a 2-month, or a 3-month cut-off. Conclusions: A delay of colonoscopies beyond 6 months after positive fecal tests is associated with a higher odds of detecting colorectal cancer. A timely follow up of patients with positive fecal tests is warranted.