The cost-effectiveness and benefit-to-harm ratio of the NHS Breast Screening Programme (NHSBSP) could be improved by adopting a risk-stratified strategy, a study in JAMA Oncology has concluded.
In a life-table model, a hypothetical cohort of 364,500 women aged 50 years, free of breast cancer received no screening, age-based screening, or risk-stratified screening. It found that targeting screening to women with higher polygenic risk reduced overdiagnosis and cost without compromising quality-adjusted life-years (QALYs) gained or breast cancer deaths prevented.
There were 1913 (95% CI 842-2714) fewer breast cancer deaths and 3819 (95% CI 2309-5291) overdiagnoses in the age-based screened vs unscreened cohort. With risk-based screening, the ratio of overdiagnosis to cancer deaths prevented increased from 0.07 at the 99th percentile of risk distribution to 0.99 at the 71st percentile and 2.01 at the 1st percentile. There were more overdiagnosed cases than breast cancer deaths prevented when screening was targeted to a risk threshold of ≤70th percentile.
Compared with no screening, age-based screening was associated with an additional 1916 QALYs (95% CI 2073-6073) at an additional cost of £41.9 million (95% CI £41.7-£69.3 million), giving an incremental cost-effectiveness ratio (ICER) of £21 854/QALY gained.
Compared with age-based screening, risk-stratified screening at the 32nd vs 70th percentile risk threshold would cost £20,066 vs £537,985 less, with 26.7% vs 71.4% fewer overdiagnoses, and 2.9% vs 9.6% fewer breast cancer deaths.
Targeting screening for women at the 71st or 70th percentile of risk distribution was the most cost-effective strategy, with a 72% probability of being cost-effective.
The research, carried out by the University College London and the University of Cambridge, suggests not screening women at lower risk could improve the cost-effectiveness of the NHSBSP and reduce overdiagnosis, while maintaining the benefits of screening.