Mo1955 A Significant Proportion of Patients Still Require Colonoscopy After CT Colonography Within the United Kingdom Bowel Cancer Screening Programme

Abstract

Background: Several European countries are implementing organized programs for colorectal cancer (CRC) screening, due to their superiority on opportunistic interventions. High-quality studies have already clarified the efficacy of the involved faecal and endoscopic tests. However, their cost-effectiveness within this context are unclear. Methods: A Markov model was constructed comparing the strategies of single sigmoidoscopy (FS) at age 58, fecal immunochemical test (FIT) every 2 years, and a sequential strategy (FS+FIT) in 100,000 subjects, based on the policy and data collected from the organized CRC screening program in the Piedmont region. In FS+FIT strategy subjects non-adherent to FS were re-invited to FIT every 2 years until age 69. Ageand sex-specific CRC incidence and mortality rates were extracted from the Piedmont cancer registry. The expected protective effect of screening on CRC incidence and mortality was derived from the literature. Direct cost analysis was carried out separately for FS and for FIT at first and subsequent rounds. All relevant resources consumed by the program were calculated for each strategy. Incremental cost-effectiveness ratios (ICER) between the different strategies were calculated. Sensitivity and probabilistic analysis were also performed. Results: Direct costs for FS and FIT at 1° and >2° rounds were estimated as ¤160, ¤33 and ¤21, respectively. Assuming the observed participation rates in the Piedmont program (FS: 30%; FIT: 42%), all the simulated strategies appeared to be effective (10-17% of CRC incidence reduction) and cost-effective, compared to the no screening scenario, with an ICER lower than ¤1,000 per life-year saved. However, FS and FS+FIT were the only strategies to be cost-saving or cost-neutral, FS being the least expensive (¤14 saving per person). FS+FIT and FS were the only non-dominated strategies, with FS+FIT being more effective and cost-effective than FS (ICER, ¤945-3,151 per lifeyear saved). At probabilistic analysis, FS+FIT strategy was the most cost-effective strategy in 83% of the scenarios. The residual uncertainty appeared to be mainly related with parameters inherent to efficacy of FIT and adherence, whilst costs did not play any significant role. Conclusions: Organized programs of CRC screening appear to be highly cost-effective, irrespectively of the endoscopic or faecal test selected. However, a sequential approach with sigmoidoscopy and FIT would appear the most cost-effective option. In the case of limited resources, a single sigmoidoscopy would appear the least expensive, but still convenient, approach.