E-ISSN 2148-5607
Original Article
Post-colonoscopy colorectal cancers in average-risk Korean subjects with a normal initial colonoscopy
1 Department of Internal Medicine, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea  
2 Department of Internal Medicine, Uijeongbu St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu, Korea  
3 MOT Cluster, Korea University of Technology and Education, Cheonan, Korea  
Turk J Gastroenterol 2016; 27: 17-22
DOI: 10.5152/tjg.2015.150286
Key Words: Colonoscopy, colonic neoplasms, colorectal cancer

Background/Aims: There are relatively few studies regarding the incidence of post-colonoscopy colorectal cancer (PCCRC) in Asian countries. We evaluated the characteristics of PCCRC in average-risk Korean subjects.


Materials and Methods: This study included subjects who were ≥50 years of age and had undergone a first completed colonoscopy between January 2001 and December 2004, at which no baseline adenoma had been detected, followed by a second colonoscopy 1–5 years later. The incidences and characteristics of advanced neoplasia in these subjects were assessed.


Results: A total of 343 subjects underwent follow-up colonoscopy within 5 years. Seventy-three (21.3%) subjects were found to have at least one adenoma on follow-up colonoscopy. Advanced adenoma was found in eight (2.3%) subjects, and non-advanced adenomas were found in 65 (19.0%). Five (1.5%) subjects were diagnosed with invasive CRC following a normal colonoscopy. The putative reason for PCCRCs was missed lesions in two (40.0%) subjects and a new cancer in three (60.0%).


Conclusion: The risk of advanced neoplasia (including PCCRCs) within 5 years after a normal baseline colonoscopy in our cohort was not low. Considering that 40% of PCCRCs were attributable to missed lesions, our results emphasize the need for technical improvement of colonoscopic examinations to improve adenoma detection.

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