Custo-efectividade de trastuzumab no tratamento de doentes com cancro da mama em estádios iniciais em Portugal.

Abstract

Despite the important advances observed in the last 25 years in the comprehension of the clinical and biological nature of breast cancer and its treatment, this disease remains a significant cause of cancer morbidity and mortality worldwide. The clinical trial Hera has demonstrated the safety and efficacy of trastuzumab in the treatment of HER2 positive (HER2+) breast cancer patients, in early stages, subsequent to surgery, chemotherapy (neoadjuvante or adjuvant) and radiotherapy, if applied. To evaluate the cost-effectiveness of 1-year trastuzumab treatment versus standard care (observation following standard adjuvant chemotherapy), in patients with HER2+ breast cancer in early stages from the societal and the Portuguese National Health Service (NHS) perspectives. A 5-state Markov model with annual transition cycles was developed to estimate the long term health and economic outcomes of HER2+ early breast cáncer patients based on HERA clinical trial results. Portuguese NHS resource use and costs were estimated from a consensus expert panel and published unit costs, respectively. Clinical and economic outcomes were discounted at 3% per annum. The incremental cost-effectiveness ratios per life year gained (LYG) and per quality adjusted life year (QALY) gained were estimated. One-way sensitivity analysis was performed. Considering a 45 year time horizon, treatment with trastuzumab was estimated to increase discounted life expectancy by 2,114 life years and quality-adjusted life expectancy by 2,009 QALYs compared to standard care. Direct and indirect costs were projected to be 61.839 euro and 19.759 euro with trastuzumab and 40.559 euro and 25.392 euro with standard of care. These results corresponded to incremental cost-effectiveness ratios of 10.067 euro and 10.595 euro assuming direct costs only, and of 7.400 euro and 7.789 euro including indirect costs, per life year gained and per QALY gained, respectively. The 1-year trastuzumab use as adjuvant therapy in HER-2+ early breast cancer patients improves survival and can be considered a cost effective therapy with a high degree of certainty in the Portuguese setting.