Can Ireland’s colorectal screening programme save more lives, save money and live within existing colonoscopy capacity limits? Findings from the MISCAN microsimulation model

OBJECTIVES: Ireland’s colorectal cancer screening programme, BowelScreen, offers biennial faecal immunochemical testing (FIT) for 60-69 year-olds. Screening sensitivity and specificity of FIT are adjusted by varying the test positivity threshold. BowelScreen uses a FIT cut-off of 225ng/ml of haemoglobin. Existing literature indicates that a lower cut-off of 50ng/ml would cost less and be more effective, but require more colonoscopies for positive screen findings, which is a key capacity constraint. The objective of this study was to determine if a more effective, less costly screening strategy exists within BowelScreen’s current colonoscopy capacity requirements. METHODS: The MISCAN cancer screening model was used to simulate 144 strategies of varying screening intervals, age ranges and FIT cut-offs. Outputs estimated were net costs, quality-adjusted life-years (QALYs) and number of colonoscopies required. RESULTS: A combination of a reduction in the FIT cut-off to 50ng/ml, an extended screening interval of 3 years and a reduced screening start age of 55 saves 20% more QALYs, reduces costs by 7%, and yields a 17% reduction in colonoscopy requirements. CONCLUSIONS: Simple changes to BowelScreen could save lives, reduce costs and relieve pressure on colonoscopy capacity.