European inter-institutional impact study of MammaPrint

AIM: To measure the impact of MammaPrint on adjuvant treatment decisions and to analyze the agreement in treatment decisions between hospitals from 4 European countries for the same patient cohort. METHODS: Breast cancer patients were prospectively enrolled and MammaPrint was assessed. Patients' clinical data without and then with MammaPrint results were sent to the different multidisciplinary teams and treatment advice was provided for each patient. RESULTS: Using MammaPrint, chemotherapy treatment advice for ER+/HER2- breast cancer patients was changed in 37% of patients by the Dutch, 24% by the Belgian, 28% by the Italian and 35% by the Spanish teams. MammaPrint increased the inter-institutional agreement in treatment advice (chemotherapy or no chemotherapy) from 51% to 75%. CONCLUSION: The results of this study indicate that MammaPrint impacts adjuvant chemotherapy recommendation. MammaPrint can decrease inter-institutional and inter-country variability in adjuvant treatment advice for breast cancer patients.