Screening colonoscopy in Chinese and Western patients: a comparative study.

Objectives: The aim of this study was to compare findings on screening colonoscopy in a Chinese cohort versus a concurrent Western cohort.
Methods: Asymptomatic adults aged 40 years or older concurrently underwent screening colonoscopy in two hospitals, one in Taiwan and the other in Seattle. The prevalence and distribution of colonic neoplasia and advanced neoplasia (defined as an adenoma >or=10 mm or with villous, high-grade dysplastic, or malignant features) were compared between the two groups.
Results: The Taiwan cohort was composed of 1,456 subjects. Colonic neoplasms were found in 214 (14.7%), advanced neoplasms in 58 (4%), and colon cancers in 4 subjects (0.3%). The Seattle cohort was composed of 3,403 subjects. Neoplasms were found in 705 (20.7%), advanced neoplasms in 166 (4.9%), and cancers in 11 subjects (0.3%). Age and male sex were risk factors for neoplasia in both groups. The adjusted risk ratio was 1.30 (95% confidence interval: 1.08-1.57) in Western versus Chinese patients. However, the prevalence of advanced neoplasms was not statistically different between the two cohorts. The Chinese cohort had a higher proportion of distal neoplasia (66.4%vs 52.6%; p= 0.0004). The sensitivity of a sigmoidoscopic screening strategy for detecting advanced neoplasia was higher in Chinese (79.3%) than in Western patients (67.5%).
Conclusions: Compared to Westerners, Chinese patients have a slightly lower prevalence of colon neoplasia (but not advanced neoplasia), more distal distribution of neoplasia, and higher likelihood of concomitant proximal advanced neoplasia and distal neoplasia. Colonoscopy is safe, well-tolerated, and a viable screening option in Chinese patients, but its advantage over sigmoidoscopy as a screening tool may be smaller.