Feasibility of observational screening colonoscopy followed by deferred polypectomy

With the increasing necessity of colorectal cancer screening, observational screening colonoscopy during which only endoscopic observation and diagnosis is performed is worth consideration. However, whether detected lesions can be correctly identified at secondary colonoscopy performed for polypectomy is unclear. Further, whether new neoplastic lesions can be detected at secondary colonoscopy has not been fully examined. This study was performed to investigate the detectability of adenomatous polyps and advanced colorectal neoplasia (ACN) at secondary colonoscopy.

Data were analyzed from individuals who underwent initial observational screening colonoscopy followed by secondary colonoscopy for polypectomy. The proportion of correct detection at secondary colonoscopy of the lesions detected at initial colonoscopy was assessed. The number and characteristics of lesions that were newly detected at secondary colonoscopy were also evaluated.

Data of 587 individuals were assessed. Among the 1 331 lesions detected at the initial colonoscopy, 1 151 (86.5%) were properly detected at the secondary colonoscopy. The proportions of correct detection at the secondary colonoscopy for ACN, non-advanced adenomas sized 5 to 9 mm, and non-advanced adenomas sized 1 to 4 mm were 100%, 95.4%, and 70.3%, respectively. In total, 175 adenomatous polyps and ACNs were newly detected at secondary colonoscopy in 112 individuals (19.1% of all individuals). Most of the lesions (165 lesions, 94.3%) were non-advanced adenomas, while advanced adenomas (5.7%) were also found.

Screening by observational colonoscopy followed by deferred polypectomy is a feasible option in terms of lesion detectability, particularly when lesions sized ≥ 5 mm are the treatment target.