Implementing a Risk-Stratified National Breast Screening Programme in the United Kingdom: a model-based cost-effectiveness analysis

BACKGROUND: Risk-stratified breast screening, where women are offered different screening intervals based on their breast cancer risk, has been proposed as a way to improve the benefits of screening in the United Kingdom National Breast Screening Programme (UK-NBSP). The aim of this study was to explore the cost-effectiveness of potential risk-stratified breast screening strategies in the UK-NBSP. METHODS: An existing validated discrete event simulation model (MANC-RISK-SCREEN)), was used to evaluate the cost-effectiveness of three risk-stratified NBSPs (risk-1; risk-2; risk-3) compared with the current UK-NBSP, two-yearly screening and no screening (life-time horizon; health service perspective; costs (£;2024)). MANC-RISK-SCREEN was modified to account for bias in risk-prediction and allocation to risk categories (risk-misclassification). Uncertainty in the results given model inputs was quantified using Probabilistic Sensitivity Analysis and one-way sensitivity analyses. RESULTS: At a cost-effectiveness threshold of £20,000 per quality-adjusted life year (QALY), 2-yearly screening was most likely to be cost-effective, followed by a risk-stratified approach whereby women at high risk (>8% ten-year risk) were screened annually and women at moderate risk (5-8% ten-year risk) bi-annually. When risk misclassification was accounted for, the ranking of risk-stratified screening strategies improved relative to universal strategies. CONCLUSIONS: Should two-yearly screening be infeasible due to resource constraints, then implementing a risk-stratified approach into the existing national breast screening programme in the UK would be a cost-effective use of healthcare resources. IMPACT: Implementation of risk-stratified breast screening in the UK national screening programme has the potential to improve cancer detection at a reasonable additional resource use and cost.