Screening for colorectal cancer in Chinese: Comparison of fecal occult blood test, flexible sigmoidoscopy, and colonoscopy

Abstract

Background & Aims: Fecal occult blood testing (FOBT), flexible sigmoidoscopy (FS), and colonoscopy are the most commonly recommended screening tests for colorectal cancer. The aim of this study was to compare the accuracy and safety of these 3 screening procedures in a general population of ethnic Chinese. Methods: Asymptomatic adults older than 50 years were recruited from the general public through health exhibitions. All enrolled subjects were offered FOBT and full colonoscopy under sedation. Advanced colonic lesions (defined as adenoma ≥ 10 mm, villous adenoma, adenoma with moderate or severe dysplasia, or invasive cancer) were recorded. Lesions at the distal 40 cm in the left colon and rectum were taken as findings of FS. Results: A total of 505 subjects (56% women; mean age ± SD, 56.5 ± 5.4 years) were enrolled, and 476 (94.3%) had a complete colonoscopy. Advanced colonic neoplasms were documented in 63 subjects (12.5%), of which 45 had lesions in the distal colon and 26 in the proximal colon. Among the 385 subjects with a normal distal colon, 14 (3.6%) had advanced lesions in the proximal colon that would be missed by FS alone. The sensitivity and specificity of FOBT for advanced colonic lesions were 14.3% and 79.2% and the sensitivity and specificity of FS were 77.8% and 83.9%, respectively. Combining FOBT with FS would not significantly improve the results of FS alone. Among these 505 subjects who underwent colonoscopy and 148 who underwent polypectomy, there was no perforation and only one occurrence of postpolypectomy bleeding recorded. Conclusions: Colonoscopy is a safe and accurate method for the screening of colorectal neoplasms in Chinese subjects.