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Am J Gastroenterol. 2009 Aug;104(8):2028-34. doi: 10.1038/ajg.2009.202. Epub 2009 May 19.

Repeat-screening colonoscopy 5 years after normal baseline-screening colonoscopy in average-risk Chinese: a prospective study.

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Institute of Digestive Disease, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong.



Although colonoscopy is considered the most accurate screening tool for colorectal neoplasm, the optimal interval of repeating a screening colonoscopy, particularly in average-risk subjects after a negative colonoscopy, is poorly defined. We determine the 5-year risk of advanced neoplasia on rescreening colonoscopy in a cohort of average-risk Chinese subjects.


We invited a cohort of asymptomatic average-risk Chinese subjects (aged 55-75 years) who were recruited in our previous screening colonoscopy studies to undergo a repeat colonoscopy at the end of 5 years. The rates of advanced colorectal neoplasia at the end of 5 years in these subjects were determined according to their baseline colonoscopy findings.


A total of 511 of the 620 eligible subjects underwent repeat-screening colonoscopy at the end of 5 years. Among them, 401 subjects had no baseline neoplasia (370 with no baseline polyps and 31 with hyperplastic polyps). In subjects with no baseline polyp, 24.6% were found to have at least one adenoma and 1.4% had advanced neoplasia on rescreening. The number needed to rescreen for one advanced neoplasia in subjects with no baseline polyp was 74 (95% confidence interval (CI), 32-168). The prevalence of advanced neoplasia at 5 years in subjects with baseline-advanced neoplasia was 20.7% (relative risk 19.6; 95% CI, 5.2-74.1; vs. subjects with no baseline polyp). The presence of baseline-advanced neoplasia (odds ratio (OR) 13.1; 95% CI, 4.1-41.7) and age in years (OR 1.11; 95% CI, 1.01-1.22) are two independent factors for development of advanced neoplasia at 5 years.


The risk of advanced neoplasia is sufficiently low 5 years after a normal screening colonoscopy in Chinese subjects.

[Indexed for MEDLINE]

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