Projecting the Prevalence and Costs of Metastatic Breast Cancer From 2015 through 2030.

Background: This study projected the number of metastatic breast cancer (mBC) cases and costs (medical and productivity) attributable to mBC through 2030 among 3 age groups: younger (aged 18-44 years), midlife (aged 45-64 years), and older women (aged 65 years and older).

Methods: We developed a stock/flow model in which women enter the mBC population at initial diagnosis (de novo stage IV) or through progression of an earlier-stage cancer. Women exit the mBC population through death. Input parameters by age and phase of treatment came from the US Census, Surveillance, Epidemiology, and End Results and peer-reviewed literature.

Results: In 2030, we estimated there would be 246 194 prevalent cases of mBC, an increase of 54.8% from the 2015 estimate of 158 997. We estimated total costs (medical and productivity) of mBC across all age groups and phases of care were $63.4 billion (95% sensitivity range = $59.4-$67.4 billion) in 2015 and would increase to $152.4 billion (95% sensitivity range = $111.6-$220.4 billion) in 2030, an increase of 140%. Trends in estimated costs were higher for younger and midlife women than for older women.

Conclusions: The cost of mBC could increase substantially in the coming decade, especially among younger and midlife women. Although accounting for trends in incidence, progression, and survival, our model did not attempt to forecast structural changes such as technological innovations in breast cancer treatment and health-care delivery reforms. These findings can motivate early detection activities, direct value-driven mBC treatment, and provide a useful baseline against which to measure the effect of prevention and treatment efforts.