RESUMEN
INTRODUCTION: The 21-gene breast cancer assay (Oncotype DX(®); Genomic Health, Inc.) is a validated diagnostic test that predicts the likelihood of adjuvant chemotherapy benefit and 10-year risk of distant recurrence in patients with hormone-receptor-positive, human epidermal growth receptor 2-negative, early-stage breast cancer. The aim of this analysis was to evaluate the cost-effectiveness of using the assay to inform adjuvant chemotherapy decisions in Mexico. METHODS: A Markov model was developed to make long-term projections of distant recurrence, survival, and direct costs in scenarios using conventional diagnostic procedures or the 21-gene assay to inform adjuvant chemotherapy recommendations. Transition probabilities and risk adjustment were taken from published landmark trials. Costs [2011 Mexican Pesos (MXN)] were estimated from an Instituto Mexicano del Seguro Social perspective. Costs and clinical benefits were discounted at 5% annually. RESULTS: Following assay testing, approximately 66% of patients previously receiving chemotherapy were recommended to receive hormone therapy only after consideration of assay results. Furthermore, approximately 10% of those previously allocated hormone therapy alone had their recommendation changed to add chemotherapy. This optimized therapy allocation led to improved mean life expectancy by 0.068 years per patient and increased direct costs by MXN 1707 [2011 United States Dollars (USD) 129] per patient versus usual care. This is equated to an incremental cost-effectiveness ratio (ICER) of MXN 25,244 (USD 1914) per life-year gained. CONCLUSION: In early-stage breast cancer patients in Mexico, guiding decision making on adjuvant therapy using the 21-gene assay was projected to improve life expectancy in comparison with the current standard of care, with an ICER of MXN 25,244 (USD 1914) per life-year gained, which is within the range generally considered cost-effective.