Real world cost of human epidermal receptor 2-positive metastatic breast cancer patients: a longitudinal incidence-based observational costing study in the Netherlands and Belgium

Currently, no country-specific metastatic breast cancer (MBC) observational costing data are available for the Netherlands and Belgium. Our aim is to describe country-specific resource use and costs of human epidermal receptor 2 (HER-2)-positive MBC in the Netherlands and Belgium, making use of real-world data. The eligibility period for patient selection was from April 2004 to April 2010. Inclusion and retrospective data collection begins at the time of first diagnosis of HER-2-positive MBC during the eligibility period and ends 24 months post-index diagnosis of MBC or at patient death. We identified 88 eligible patients in the Netherlands and 44 patients in Belgium. The total costs of medical treatment and other resource use utilisation per patient was €48,301 in the Netherlands and €37,431 in Belgium. Majority of costs was related to the use of trastuzumab in both countries, which was 50% of the total costs in the Netherlands and 56% in Belgium respectively. Our study provides estimates of resource use and costs for HER-2-positive MBC in the Netherlands and Belgium. We noticed various differences in resource use patterns between both countries demonstrating caution is needed when transferring cost estimates between countries.