Breast cancer has become the most common cancer in Thai women since 2005. Unfortunately two thirds of the patients were diagnosed at advanced breast cancer (ABC) stage. Furthermore, most of these women were under the Universal Coverage by the government which does not provide sufficient coverage for certain critical medical treatments for ABC patients. The cost of treatments is even more of a pressing issue in Thailand. This study aimed to evaluate the cost-effectiveness of exemestane (EXE), a steroidal aromatase inhibitor (SAI), as treatment therapy following adjuvant non-steroidal aromatase inhibitor (NSAI) for hormonal responsive ABC in Thailand.
A Markov model was used to estimate the relevant costs and health outcomes over the patients' lifetimes using a social cost and benefit perspective. All future costs and outcomes were discounted at a rate of 3% per annum. The efficacy and cost of EXE and chemotherapy were based on a clinical trial that included a total of 18 post-menopausal hormonal responsive ABC patients. Utility values were derived directly from all patients using EQ-5D. Primary outcomes of interest were lifetime costs, quality adjusted life-years (QALYs) gained, and the incremental cost-effectiveness ratio (ICER) in US ($) per QALY gained. One-way and probabilistic sensitivity analyses (PSA) were conducted to investigate the effect of parameter uncertainty.
In base case analysis, the EXE group had better clinical outcomes and lower lifetime costs. The incremental cost per QALY gained was US $-2,747 per QALY. The acceptability curve showed that the probability of EXE being cost-effective was 97% at the willingness to pay of 1 time of Thai Gross National Income per capita (GNI per capita), approximately US $4,673 per QALY gained.
At a social cost of paying 1 GNI per capita, EXE is highly effective and cost-saving regimen for the first-line treatment of post-menopausal ABC with hormone positive receptor in Thailand. This study provides key relevant information aiding policy makers to make informed decision making regarding resource allocation to include EXE into reimbursement plan.
Faculty of Medicine, Chiang Mai University
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All authors have declared no conflicts of interest.