Study design and patient recruitment for the Japan Polyp Study

Abstract

Background: The Japan Polyp Study (JPS) Workgroup was established in 2000 to evaluate colonoscopic follow-up surveillance strategies. The JPS was a multicenter randomized controlled trial designed to evaluate follow-up surveillance strategies in patients who had undergone two complete colonoscopies for control of colorectal cancer, with removal of all detected polyps. The aim of the present analysis was to assess the patient recruitment and whether the clinical characteristics were adequate for enrollment at the participating centers. Materials and methods: Among referrals for colonoscopy at the eleven participating centers, all patients who were 40-69 years old, without a family or personal history of familial polyposis, Lynch syndrome, inflammatory bowel disease, or a personal history of polypectomy with unknown histology, and had no invasive colorectal cancer or colectomy, were considered for inclusion from February 2003. Results: Among 4, 752 referrals, a total of 3, 926 patients with a mean age of 57.3 (range 40-69) years, including 2, 440 (62%) males, were included in the JPS. The participation rate was 83%. Among them, a total of 2, 757 patients who had undergone two complete colonoscopies with removal of all detected polyps were eligible, giving an eligibility rate of 70% (2, 757 of 3, 926). Among the eligible patients, 2, 166 were assigned to randomized groups, and 591 patients to a nonrandomized group. The last steps of data lock, analysis, and complete histopathological assessment based on a pathology review are ongoing. Conclusion: Eligible patients recruited for the JPS were successfully assigned on the basis of the expected sample-size calculation. © 2014 Sano et al.