Objective: To study the distribution characteristics of colorectal neoplasm and evaluate the implication for colorectal cancer screening.
Methods: A total of 17,939 colonoscopies were performed in the National Center of Colorectal Surgery between October 2004 and June 2009. Characteristics of colorectal neoplasm including anatomical distribution, sex, and age were investigated.
Results: Colorectal neoplasm was found in 24.8% (4450/17,939) of the patients during colonoscopy, including adenomatous polyp (n=3410, 19.0%) and adenocarcinoma (n=1040, 5.8%). The prevalence of colorectal neoplasm was higher in male and significantly increased in patients older than 40 years. 63.3% of the lesions located at the distal colon (sigmoid colon and rectum) and 36.7% at the proximal colon (36.7%). In patients with adenomatous polyp, 52.8% (1802/3410) of the lesions were at the distal colon, 30.8% (1049/3410) at the proximal colon, and 16.4% (559/3410) at both distal and proximal colon. In patients with carcinoma (n=1040), 921 (88.6%) lesions located at the distal colon, 118 (11.3%) at the proximal colon, and 1 (0.1%) at both segments.
Conclusion: Sigmoidoscopy is inadequate for colorectal cancer screening as compared to colonoscopy.