Purpose: One-year adjuvant trastuzumab (AT) therapy, with or without anthracyclines, increases disease-free and overall survival in early-stage HER2/neu-positive breast cancer. We sought to evaluate the cost effectiveness of these regimens, which are expensive and potentially toxic.
Methods: We used a Markov health-state transition model to simulate three adjuvant therapy options for a cohort of 49-year-old women with HER2/neu-positive early-stage breast cancer: conventional chemotherapy without trastuzumab; anthracycline-based AT regimens used in the National Surgical Adjuvant Breast and Bowel Project B-31 and North Central Cancer Treatment Group N9831 trials; and the nonanthracycline AT regimen used in the Breast Cancer International Research group 006 trial. The base case used treatment efficacy measures reported in the randomized clinical trials of AT. We measured health outcomes in quality-adjusted life-years (QALYs) and costs in 2005 United States dollars (US$) and subjected results to probabilistic sensitivity analysis.
Results: In the base case, the anthracycline-based AT arm has an incremental cost-effectiveness ratio (ICER) of $39,982/QALY, whereas the nonanthracycline AT arm is more expensive and less effective; this result is insensitive to changes in recurrence rates, but if there is no benefit after 4 years, ICERs exceed $100,000/QALY for both AT arms. Results are moderately sensitive to variation in breast cancer survival rates and trastuzumab cost, and less sensitive to variations in cardiac toxicity.
Conclusion: AT has an ICER comparable to those for other widely used interventions. Longer clinical follow-up is warranted to evaluate the long-term efficacy and toxicity of different AT regimens.