Inter-endoscopist variation in polyp and neoplasia pick-up rates in flexible sigmoidoscopy screening for colorectal cancer

Background: The Norwegian Colorectal Cancer Prevention study is an ongoing flexible sigmoidoscopy (FS) screening trial for colorectal cancer. Twenty-one thousand average-risk individuals, aged 50 - 64 years, living in two separate areas in Norway were randomly drawn from the Population Registry and invited to once-only screening flexible sigmoidoscopy. Examinations were performed over 3 years, at 2 centres, by 8 different endoscopists, using the same type of equipment. The aim of the present study was to investigate possible differences between endoscopists in detecting individuals with polyps, adenomas and advanced lesions ( adenomas with severe dysplasia and/or villous components and/or size larger than 9 mm and carcinoma) in flexible sigmoidoscopy screening. Methods: The present trial comprises data from 8822 individuals, aged 55 - 64 years, who have undergone a flexible sigmoidoscopy. In the study period, all lesions detected by the different endoscopists were registered. Tissue samples were taken from all lesions detected. Results: Detection rates varied significantly between endoscopists, ranging from 36.4% to 65.5% for individuals with any polyp, from 12.7% to 21.2% for any adenoma and from 2.9% to 5.0% for advanced lesions. In a multiple logistic regression model, the performing endoscopist was a strong independent predictor for detection of individuals with polyps ( P < 0.001), adenomas ( P < 0.001) and advanced lesions ( P = 0.01). Conclusion: Detection rates for colorectal lesions vary significantly between endoscopists in colorectal cancer screening. Establishing systems for monitoring performance in screening programmes is important. Supervised training and re-certification for endoscopists with poor performance should be considered.