Flexible sigmoidoscopy as a colorectal cancer screening test in the general population: recruitment phase results of a randomized controlled trial in Lombardia, Italy

A two arm multicentre randomized controlled trial is in progress to evaluate the efficacy of flexible sigmoidoscopy (FS) as a screening test for colorectal cancer in the general population. AIMS: To determine the acceptance rate and feasibility of FS as a colorectal cancer screening test in average-risk asymptomatic volunteers. Average-risk, asymptomatic subjects, aged 55-64 years and assisted by 244 general practitioners (GPs) in Lombardy, Italy, were invited by postal questionnaire (PQ) to enter a study for the prevention of colorectal cancer and asked to indicate their interest in, and willingness to undergo, screening: those responding positively were randomized to the intervention or control arms. GPs were trained in colorectal cancer screening and proposed free FS to their patients randomized to the intervention arm. All sigmoidoscopies were performed by experienced endoscopists. Small polyps were removed at FS. Colonoscopy was indicated for high risk polyps (size more than 5 mm, more than two adenomas, villous histology, severe dysplasia or malignancy). 40,945 subjects were invited. 667 PQs were returned undelivered due to postal failure. 7,892 (19.59%) subjects responded, 2,116 of whom (26.81%) were not included, presenting 1 or more exclusion criteria. We randomized 5,778 volunteers and performed 1,582 sigmoidoscopies out of 2,885 subjects in the intervention arm (54.84% acceptance rate). Although the screening procedure had a good attendance rate in the intervention group, involvement of the people invited was lower than expected. Future FS screening programmes will require a keener focus on recruitment strategies, mainly with participation of GPs.