174P Modelling cost-effectiveness of breast cancer screening: Mammography leads to substantial cost savings for breast cancer treatment

This is the authors' abstract. We don't add key points for this paper.

Controversies exist around the public health benefit of breast cancer (BC) screening. Early detection has proven benefits in terms of improved survival and decreased treatment morbidity. With recent advances in treatment and technologies resulting in increased costs for BC therapy, the cost effectiveness of screening is unknown. The purpose of this study was to use current BC treatment costs to determine cost-effectiveness of mammographic screening. Contemporary Canadian cost estimates based on 2023 treatment standards were incorporated into user-created scenarios run on the Canadian Partnership Against Cancer/Statistics Canada OncoSim BC microsimulation model to estimate the impact of various regimens for screening on outcomes and on overall costs of screening and treatment. We ran four scenarios that simulated a birth cohort (aged 40 in 2015) for no screening, biennial screening (ages 50-74 and 40-74), and annual screening (age 40-74). Canadian per-case BC treatment costs tabulated in our previous work (all values in Canadian dollars, $1 CAD = $0.74 USD = € 0.68) increased markedly from $14,505 for in situ disease, $39,263, $76,446, $97,668 and $370,398 for Stages I through IV respectively. Costs also vary among subtypes; for Stage III, from $75,954 (HER2+) to $110,798 (triple negative) and $117,269 (HR+). Cost per screening mammogram was $71. Our analysis shows that for 1000 women, initially at age 40, the lifetime cost of screening varies from $0 (no screening), $810,000 (biennial 50-74), $1.14M (biennial 40-74) to $2.2M (annual 40-74) while corresponding therapy costs are $14.9M, $12.4M, $11.8M and $10.6M. Number of BC deaths averted per 1000 women screened for each schedule compared to no screening were 9.3, 11.0 and 14.3 respectively (life-years gained 113, 161, 214). Screening annually aged 40-74 is associated with a net savings of $1878/woman or $442.8M annually to the Canadian health system. Although screening costs rise according to the number of lifetime screens, they are easily offset by reduced breast cancer therapy costs. Increased population level BC screening yields significant net savings to the health system while averting breast cancer deaths.