EVALUATING PREDICTED RESOURCE USE, COST AND QUALITY OF LIFE OUTCOMES OF COLORECTAL CANCER SCREENING WITH THE FAECAL IMMUNOCHEMICAL TEST IN ENGLAND USING ECONOMIC MODELLING

Purpose: Biennial colorectal cancer screening using the guaiac faecal occult blood test (gFOBT) is in place in England for people between 60 and 74 years of age. The faecal immunochemical test (FIT) is used in other national screening programmes in Europe, but data on population-level FIT screening had not previously been available in a UK setting. The purpose of the study was to estimate the long-term resource use, cost and health-related quality of life outcomes of using FIT compared to gFOBT for colorectal cancer screening in England.

Method(s): We constructed a Markov state-transition model based on previous economic modelling carried out in the context of the UK NHS Bowel Cancer Screening Programme (NHSBCSP). We used results from a 2014-2015 pilot study of the introduction of FIT screening in two of the five screening hubs in England to update the model with test performance data for FIT vs. gFOBT at a range of cut-off values for positive FIT. Other model parameters were taken from NHSBCSP data, national cost datasets and published sources. Results were extrapolated to a lifetime time horizon and probabilistic sensitivity analyses were carried out to assess the effect of parameter uncertainty on the study conclusions.

Result(s): The results from the economic model suggest that FIT is associated with lower costs and better quality of life outcomes than gFOBT at all FIT cut-off values considered in the analysis. The findings were driven by lower rates of cancer incidence in the long term with FIT screening, as predicted by the modelled extrapolation. The model predicted an increase in the total incremental colonoscopy costs by a factor of 25 between the highest (180µg/g) and the lowest (20µg/g) FIT cut-off value in the model. However, a five-fold increase in cancer management savings over the same range resulted in greater overall cost savings at lower cut-off values. Total incremental quality-adjusted life years also increased as the FIT cut-off value decreased.

Conclusion(s): Although more favourable quality of life and cost outcomes compared to gFOBT are predicted at lower FIT cut-off values, the large number of referrals at these levels estimated by the model may present a significant challenge to colonoscopy services. Therefore, the choice of FIT cut-off value upon introduction of the test must take into account short-term capacity constraints in the healthcare system.