Cost-effectiveness of colorectal cancer screening programmes using sigmoidoscopy and immunochemical faecal occult blood test.

Several European countries are implementing organized colorectal cancer (CRC) screening programmes using faecal immunochemical test (FIT) and/or flexible sigmoidoscopy (FS), but the cost-effectiveness of these programmes is not yet available. We aimed to assess cost-effectiveness, based on data from the established Piedmont screening programme. Using the Piedmont programme data, a Markov model was constructed comparing three strategies in a simulated cohort of 100,000 subjects: single FS, biennial FIT, or sequential strategy (FS + FIT offered to FS non-responders). Estimates for CRC incidence and mortality prevention were derived from studies of organized screening. Cost analysis for FS and FIT was based on data from organized programmes. Incremental cost-effectiveness ratios (ICER) between the different strategies were calculated. Sensitivity and probabilistic analyses were performed. Direct costs for FS, and for FIT at first and subsequent rounds, were estimated as €160, €33, and €21, respectively. All the simulated strategies were effective (10-17% CRC incidence reduction) and cost-effective vs. no screening (ICER <€1000 per life-year saved). FS and FS + FIT were the only cost-saving strategies, with FS least expensive (€15 saving per person invited). FS + FIT and FS were the only non-dominated strategies. FS + FIT were more effective and cost-effective than FS (ICER €1217 per life-year saved). The residual marginal uncertainty was mainly related to parameters inherent to FIT effectiveness and adherence. Organized CRC screening programmes are highly cost-effective, irrespective of the test selected. A sequential approach with FS and FIT appears the most cost-effective option. A single FS is the least expensive, but convenient, approach.