Virtual colonoscopy, optical colonoscopy, or fecal occult blood testing for colorectal cancer screening: results of a pilot randomized controlled trial

Background: No head-to-head randomized controlled trials have demonstrated the superiority of one colorectal screening modality over another in reducing colorectal cancer mortality. We conducted a pilot randomized controlled trial of fecal occult blood testing (FOBT), optical colonoscopy (OC), and virtual colonoscopy (VC), to inform the planning of a larger evaluative trial. Methods: Eligible patients (aged 50 to 70) were recruited from five primary care practices in Hamilton, ON, Canada, between March 23, 2010 and August 11, 2010, and randomized 1:1:1 in a parallel design using an automated, centralized telephone service to either FOBT, OC, or VC. To reflect conventional practice, patients received no additional reminders to complete their allocated screening test beyond those received in usual practice. The primary outcome was completion of the assigned screening procedure. Results of the index test and any follow-up investigations were ascertained at 6 months. Participants, caregivers, and outcome assessors were not blinded to group assignment. The trial was stopped early due to lack of ongoing funding. Results: A total of 198 participants were enrolled, of whom 67 were allocated to FOBT, 66 to OC, and 65 to VC. The allocated screening procedure was completed by 43 (64 %) subjects allocated to FOBT (95 % confidence interval [CI], 52-75 %), 53 (80 %) subjects allocated to OC (95 % CI, 69-88 %), and 50 (77 %) subjects allocated to VC (95 % CI, 65-85 %); because the trial stopped early, we had insufficient statistical power to detect clinically relevant differences in completion rates. During 6 months follow-up, colorectal adenomas were detected in 0 (0 %) subjects allocated to FOBT, 12 (18 %) subjects allocated to OC, and 2 (3 %) subjects allocated to VC. One subject in the OC arm had histological evidence of high-grade dysplasia. No subjects were diagnosed with colorectal cancer. Conclusions: In this pilot randomized controlled trial of colorectal cancer screening in a primary care setting, 64-80 % of subjects completed their allocated screening test. These findings may be of value to investigators planning clinical trials to evaluate the effectiveness of colorectal cancer screening.