Colorectal neoplasm in asymptomatic Asians: a prospective multinational multicenter colonoscopy survey

Background: Colorectal neoplasm is rapidly increasing in Asia, but a guideline for screening is not available. Objective: To evaluate the characteristics of colorectal neoplasm in asymptomatic Asian subjects. Design: Prospective cohort study. Setting: Multinational multicenters, including both primary and referral centers in Asia. Patients: A total of 860 consecutive asymptomatic adults undergoing screening colonoscopy in 11 Asian cities from July 2004 to December 2004. Patients under 16 years old; those patients with a colorectal resection history, colonoscopies, or barium enema within 5 years; symptoms suggestive of colorectal diseases; and those who had undergone surveillance colonoscopy were excluded. Main Outcome Measurements: The incidence and distribution of colorectal neoplasm and advanced neoplasm. Results: The mean age (+/- SD) was 54.4 +/- 11.6 years; 471 were men (54.8%). The prevalence of colorectal neoplasm and advanced neoplasm was 18.5% and 4.5%, respectively Male sex, advancing age, and a family history of colorectal cancer were risk factors for advanced neoplasm. Of the 168 patients with colorectal neoplasm, 76 had distal neoplasm only (45.2%), 66 had proximal neoplasm only (39.3%), and 26 had both proximal and distal neoplasms (15.5%). Although the presence of distal advanced neoplasm was a significant risk factor for proximal advanced neoplasm, 14 of the 758 subjects without distal neoplasm had proximal advanced neoplasm (1.8%). Limitations: The small number of enrolled subjects, especially from certain ethnic groups. Conclusions: The overall prevalence of advanced colorectal neoplasm in asymptomatic Asians is comparable with the West. Male sex, advancing age, and a family history of colorectal cancer were associated with a higher risk of advanced neoplasm.