Purpose:
We estimate how different combinations of screening technologies and screening intervals would alter these outcomes in the Australian setting, for higher-risk women.
Sample/setting:
Population-based breast cancer screening has been shown to reduce mortality rates; however, adopting a more risk-stratified approach may improve the balance between its benefits and potential harms, particularly for women at higher risk of breast cancer and those with increased breast density.
Procedures:
We used the Policy1-Breast micro-simulation model to evaluate risk-stratified breast cancer screening protocols beginning in 2025, projecting outcomes over the next decade. The model accounts for screening test sensitivity ranging from 10% to 50% higher than digital mammography, aligning with published estimates for various screening technologies assessed in large populations. Screening intervals are either biennial (current practice) or annual, with scenarios including targeted screening commencement from age 40, 45 or 50. Interventions target a higher-risk cohort - approximately 20% of screening females aged 50 to 74.
Results:
We estimate a significant reduction in mortality could be achieved in the higher-risk group (up to ~30% relative reduction), with a total of up to 842 deaths prevented over 10 years at a population level, along with a reduction in large, nodal, grade 3 invasive breast cancers (up to 25% at a population level), and a 47% reduction in interval cancers (50 versus 90 per 100,000 women) for the higher-risk group. Overdiagnoses would be expected to increase at a population level, with a potential 1.8-fold increase in the higher-risk group.
Conclusions and clinical implications:
The modelled interventions in this study illustrate the potential benefits and limitations of different risk-targeted breast screening protocols. These findings could serve as a foundation for designing and planning evaluations and clinical trials of risk-based breast cancer screening in Australia.