2021 Volume 59 Issue 4 Pages 400-410
Background: Observational screening colonoscopy (during which only endoscopic observation and diagnosis are performed) followed by deferred polypectomy is worth consideration as a safe option in colorectal cancer screening. However, whether detected lesions can be correctly identified during secondary colonoscopy performed for polypectomy is unclear. Furthermore, in order to avoid an excessive increase in the number of colonoscopies caused by deferred polypectomy, it is necessary to assess whether colorectal diminutive adenomas without findings of advanced histology can be followed without polypectomy. In this study, we examined those issues using the data of individuals who had undergone observational screening colonoscopy and assessed the feasibility of observational screening colonoscopy.
Methods: The data of individuals who underwent initial observational screening colonoscopy at the Cancer Screening Center of the National Cancer Center in Tokyo were used to assess the following two issues: (I) lesion detectability during secondary colonoscopy performed for polypectomy following initial observational screening colonoscopy and (II) clinical course in terms of the incidence of advanced colorectal neoplasia (ACN) in individuals in whom only diminutive colorectal adenomas were detected during initial screening colonoscopy and were followed without polypectomy.
Results: (I) All ACNs and most of the non-advanced adenomas sized ≥5 mm (95.4%) detected during initial observational screening colonoscopy were correctly identified during secondary colonoscopy, while approximately 30% of the diminutive colorectal adenomas sized <5 mm were not identified during secondary colonoscopy. (II) The 5-year cumulative incidence of ACN was very low (1.4%), even with untreated diminutive colorectal adenomas. None of the untreated diminutive colorectal adenomas progressed to ACN during the median follow-up period of 60.7 months.
Conclusions: It may be acceptable to follow diminutive colorectal adenomas without polypectomy. Observational colonoscopy followed by deferred polypectomy is a feasible screening option when ACN and adenomas sized ≥5 mm are the treatment targets.
