Simulation modeling of change to breast cancer detection age eligibility recommendations in Ontario, 2002–2021

PURPOSE: The purpose of this project was to demonstrate the development and use of a decision support tool based on simulation modeling of breast cancer screening to evaluate the implications for the provision of health services and the economic impact of extending routine radiographic screening for breast cancer to women in the 40-49 age group between 2002 and 2021. METHODS: The main method was computer simulation with a Markov model that used published estimates of population size by age group, breast cancer prevalence and incidence, screening program participation rate, sensitivity and specificity of the screening test and diagnostic test, stage transition probabilities, directed diagnosis rates and costs. FINDINGS: The model predicted that changes to age eligibility requirements would result in the detection of an additional 6610 women with breast cancer in Ontario requiring treatment, at an additional cost of 795 Canadian per case. These costs include those related to screening, diagnosis and initial treatment and apply to the 20-year period. CONCLUSIONS: The model provided a useful decision support tool for those planning and implementing breast cancer screening programs.