Flexible sigmoidoscopy screening for colorectal neoplasia in average-risk people: evaluation of a five-year rescreening interval.

Objective: To determine the prevalence of colorectal neoplasia detected by rescreening people with average risk five years after initial screening by flexible sigmoidoscopy.

Design: Prospective survey of results of a colorectal cancer screening program.

Participants: People aged 55-64 years with no symptoms or family history of colorectal cancer who were recruited from the community for flexible sigmoidoscopy screening five years previously (July 1995 to December 1996) and had no colorectal neoplasms detected.