INCIDENCE-BASED COST-OF-ILLNESS MODEL FOR METASTATIC BREAST CANCER IN THE UNITED STATES

Objectives: This study aims to estimate the annual U.S. societal costs associated with treatment of metastatic breast cancer (MBC) patients using an incidence-based cost-of-illness (COI) framework. Methods: An incidence-based COI model was constructed in which MBC patients were simulated from diagnosis through active treatment, palliative care, and death over 5 years. Key model parameters included: annual incidence of breast cancer in the metastatic stage, utilization of cancer therapies and other medical care resources, treatment-related adverse events, unit costs, work days missed by patient and caregiver, and wage rates. Overall survival was based on SEER data and costs were assigned to living patients monthly, according to their disease management phase. The outcomes measures were total discounted societal costs, cost/year, and cost/patient-year. Results: The annual incidence of MBC in the United States in 2007 was estimated to be 49,674 patients ( de novo and progressed from earlier stages). The total discounted cost to society attributable to MBC was $12.2 billion for the incident cohort, or $98,571 per patient-year. The 5-year direct medical cost of this incident cohort was $9.3 billion, or $75,415 per patient-year. Treatment-related costs (active treatment, toxicity management, and medical follow-up) contributed 44 percent of MBC expenditure, followed by palliative/best supportive care costs (31 percent). Lost productivity accounted for approximately 21 percent of the total cost ($2.6 billion over 5 years or $21,153 per patient-year). Conclusions: The societal burden of MBC in the United States is substantial. Earlier detection and effective treatment could lead to a significant decrease in costs while improving overall disease prognosis.