RESUMO
BACKGROUND: Adjuvant chemotherapy with trastuzumab for HER2 positive breast cancers has brought considerable benefits to disease-free survival and overall survival. OBJECTIVE: To conduct a cost-effectiveness analysis of the treatment of patients with early and locally advanced HER2 positive breast cancer, within the scope of the Brazilian public health system, comparing adjuvant chemotherapy with and without trastuzumab, for 1 year of treatment. METHODS: A 4-state Markov model was developed to estimate strategy costs and outcomes. RESULTS: Based on the proposed model, we verified an incremental benefit of trastuzumab therapy compared to treatment without trastuzumab with 0.84 quality-adjusted life years (QALY) and 1.16 life years gained (LYG). The use of adjuvant chemotherapy with trastuzumab has an ICER of US$19,599.26 for each quality-adjusted life year and US$14,180.68 for each life year gained in relation to chemotherapy without trastuzumab. CONCLUSION: In Brazil, adjuvant chemotherapy with trastuzumab may be considered cost-effective only if a cost-effectiveness threshold is stipulated with the value starting at three times the Brazilian GDP per capita for QALY or two times the Brazilian GDP per capita for LYG, from health system perspective.