Brief Reports
Copyright ©The Author(s) 2005. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Aug 14, 2005; 11(30): 4731-4734
Published online Aug 14, 2005. doi: 10.3748/wjg.v11.i30.4731
Prevalence of advanced colonic polyps in asymptomatic Chinese
Hui-Hsiung Liu, Meng-Chen Wu, Yeh Peng, Ming-Shiang Wu
Hui-Hsiung Liu, Graduate Institute of Public Health, Taipei Medical University, Taipei, Taiwan, China
Meng-Chen Wu, Yeh Peng, Taipei Institute of Pathology, Taipei, Taiwan, China
Ming-Shiang Wu, Division of Gastroenterology, Department of Internal Medicine, National Taiwan University Hospital; Department of Primary Care medicine, School of Medicine, National Taiwan University, Taipei, Taiwan, China
Author contributions: All authors contributed equally to the work.
Correspondence to: Dr. Ming-Shiang Wu, Department of Internal Medicine, National Taiwan University Hospital, No. 7, Chung San S. Road, Taipei, Taiwan, China. stanley@ha.mc.ntu.edu.tw Telephone: +886-2-23123456-5410 Fax: +886-2-23947899
Received: March 9, 2004
Revised: February 10, 2005
Accepted: February 15, 2005
Published online: August 14, 2005
Abstract

AIM: To investigate the prevalence of advanced polyps in asymptomatic Chinese and to determine the risk of proximal advanced colonic polyps in subjects with and without polyps in the distal colon.

METHODS: Data were collected prospectively during colonoscopic examinations performed in 5 973 subjects as part of health evaluation at our unit from December 1997 to December 2003. Polyps were considered advanced, if they were larger than 10 mm or were tubovillous, villous or malignant. Proximal colon was defined as the splenic flexure and more proximal portions of the colon.

RESULTS: Colon polyps were detected in 971 (16.3%) subjects (613 males and 358 females) with their mean age being 56.6 ± 10.7 years. Advanced polyps were noted in 199 (3.3%) individuals. Subjects were sub-classified according to the location of polyps into three groups: distal (569, 58.6%), proximal (284, 29.2%), and combined proximal and distal (118, 12.2%) groups. Subjects with advanced polyps in these three groups were 95 (9.8%), 56 (5.8%), and 48 (4.9%) respectively. In the 48 subjects with advanced combined polyps, 13 advanced polyps were distributed at the distal colon, 17 at the proximal colon, and 18 at both. Eighteen colon cancers including 12 at sigmoid and 6 at ascending colon were confirmed by final pathology. The relative risk for advanced proximal polyp according to distal findings was 3.1 (95%CI: 1.3-7.4) for hyperplastic polyp, 2.7 (95%CI: 1.4-5.3) for tubular polyp and 13.5 (95%CI: 5.1-35.4) for advanced polyp as compared to that for no polyp. However, 56 (28.2%) of 199 subjects with advanced polyps had no index polyps at the distal colon and might go undetected under sigmoidoscopic screening.

CONCLUSION: Although distal lesions can predict the risk of advanced proximal polyps, a substantial portion of Chinese with advanced proximal polyps is not associated with any distal sentinel lesions. These data have implications for screening policy of colon cancers in Taiwanese Chinese.

Keywords: Colon polyp; Colonoscopy; Screening; Epidemiology