Objectives: The 2007 National Health Service Cancer Reform Strategy includes a proposed extension of the UK breast screening program to women aged 47 to 49 years. The aim of this study is to undertake a preliminary assessment of this proposal to identify the key factors determining its cost-effectiveness and to determine whether there is sufficient uncertainty that requires more thorough analyses.
Methods: An economic model was constructed. For simplicity, the health impact of screening was estimated by calculating the lives saved through shifts in prognostic group. A "plausible bounds" approach was used to derive distributions for model parameters for probabilistic sensitivity analysis. UK data were used to populate the model.
Results: The cost-effectiveness of the extension is estimated to be pound27,400 per quality-adjusted life-year (QALY) with a 29% probability of cost-effectiveness at a threshold of pound20,000 per QALY. The deterministic estimate of benefit becomes negative if the anxiety due to a false-positive result is set at 0.028 QALYs. Including a small positive benefit from a negative screen has a dramatic impact on the cost-effectiveness of screening. The impact of other factors appears less marked.
Conclusions: Because the vast majority of women aged 47 to 49 years will test negative when screened for breast cancer and most of those who test positive will actually be free of the disease, the psychological impacts of screening are likely to drive cost-effectiveness for this age group. Therefore, a research priority should be to better understand and quantify these effects.