Burden of breast cancer with brain metastasis: a French national hospital database analysis

Incidence of breast cancer with brain metastases (BCBM) is increasing, especially among patients over-expressing HER2. Epidemiology on this sub-type of cancer is scarce, since cancer registries carry no information on the HER2 status. A retrospective database analysis was conducted to estimate the burden of BCBM, especially among HER2-positive patients in a secondary objective.

Patients with a new diagnosis of BCBM carried out between January and December 2008 were identified from the national hospital database using the International Disease Classification. Patients receiving a targeted anti-HER2 therapy were identified from the national pharmacy database. Hospital and pharmacy claims were linked to estimate the burden of HER2-positive patients. Data on hospitalizations were extracted to describe treatment patterns and healthcare costs during a 1-year follow-up. Predictors of treatment cost were analyzed through multi-linear regression analysis.

Two thousand and ninety-nine BCBM patients were identified (mean age (SD) = 57.8 (13.6)), of whom 12.2% received a targeted anti-HER2 therapy; 79% of patients had brain metastases associated with extracranial metastases, and the attrition rate reached 82%. Patients received mostly palliative care (47.4%), general medical care (40.6%), and chemotherapy (35.0%). The total annual hospital cost of treatment was 8,426,392€, representing a mean cost of 22,591€ (±14,726) per patient, mainly influenced by extracranial metastases, surgical acts, and HER2-overexpression (p < 0.0001).

The database linkage of hospital and pharmacy claims is a relevant approach to identify sub-type of cancer. Chemotherapy was widely used as a systemic treatment for breast cancer rather than for local treatment of brain metastases whose morbi-mortality remains high. The variability of treatment costs suggests clinical heterogeneity and, thus, extensive individualization of protocols.