Background: Pilot studies are currently underway to investigate the use of flexible sigmoidoscopy as a screening tool for colorectal cancer. Estimates of the sensitivity of this investigation in detecting adenomas and carcinomas frequently assume a complete examination to 60 cm in all cases. This study seeks to determine the depth of insertion of flexible sigmoidoscopy in asymptomatic volunteers, and to examine the causes and implications of an incomplete examination.
Methods: A prospective study of flexible sigmoidoscopy in asymptomatic volunteers was conducted. The maximum depth of insertion was measured in all cases, and a database compiled of patient characteristics, discomfort and endoscopic difficulty.
Results: Independent risk factors for reduced depth of insertion were female sex, previous abdominal surgery in females, high expectation of pain in females and poor bowel preparation. The procedure was considered difficult in 33% of cases.
Conclusions: Estimates of the efficacy of flexible sigmoidoscopy as a colorectal cancer screening modality should take into account the relatively high rate of incomplete studies, particularly in women.