Objective: Breast cancer remains the highest incident cancer among females in the United States and previous research suggests that a considerable portion of patients will eventually progress to the metastatic phase of the disease. This paper provides the first estimate of the lifetime direct costs of treating metastatic disease for one annual diagnostic cohort of breast cancer patients.
Methods: Incidence rates were combined with US population counts to estimate the number of breast cancer cases diagnosed in 1994. Estimates of progression to metastatic disease (from Canadian provincial cancer registry data), costs of care (derived from patients' claims histories), survival (from SEER data), and national mortality rates (from US Census Bureau) were integrated, using Statistics Canada's Population Health Model (POHEM) to calculate lifetime costs.
Results: This study estimates that more than 40% of the women diagnosed with breast cancer will progress to metastatic disease. On average, women with metastatic disease are expected to live 3 years and to incur direct treatment costs of approximately dollar 60,000 per case, resulting in a total lifetime cost for the cohort of almost dollar 4.2 billion.
Conclusions: The high rate of recurrence of breast cancer argues for the development of interventions that can prevent or delay the onset of metastatic disease. These estimates of lifetime costs and the methodology on which they are based can be used to evaluate the cost-effectiveness of such secondary prevention strategies. These estimates also can serve as a benchmark against which the lifetime costs of treating other diseases can be assessed.