The interval between flexible sigmoidoscopy screening examinations can be expanded beyond five years.

Background/Aims: As one of the methods for colorectal cancer screening, asymptomatic average-risk persons aged ≥50 years are recommended to undergo flexible sigmoidoscopy screening every 5 years. We evaluate whether the interval between examinations can be extended beyond 5 years. Methodology: A total of 192 asymptomatic average-risk subjects were studied, all of whom had undergone a initial negative examination on a flexible sigmoidoscopy screening at age ≥50 years and a second examination at least 3 years later. The study population was divided into three groups according to the interval between examinations, which was 3-5 years in Group A, 5-6 years in Group B, and 6-8 years in Group C. Results: The incidence of neoplasms was compared among the three subjects groups, and it was found to be similar: 11/96 (11.5%) in group A, 4/55 (7.3%) in group B, and 5/41 (12.2%) in group C. All detected adenomas were less than 10mm in diameter, and none contained a villous component or high-grade dysplasia. No cancers were found in the study. Conclusions: The results suggest that the interval for screening sigmoidoscopy may be extended beyond 5 years in persons showing negative results on an initial examination.