A Canadian Economic Analysis of U.S. Oncology Adjuvant Trial 9735

Objectives: Recent results of the U.S. Oncology Adjuvant Trial 9735 demonstrated significant disease-free survival and overall survival benefits for docetaxel and cyclophosphamide (TC) compared with doxorubicin and cyclophosphamide (AC) in the adjuvant treatment of operable invasive breast cancer. Based on clinical data from the 9735 study, we evaluated the lifetime cost-effectiveness of TC compared with AC from the perspective of the Canadian publicly funded health care system. Methods: A Markov model was developed to estimate the incremental cost per quality-adjusted life-year gained and per life-year gained. Monthly survival and risk of disease recurrence up to 7 years were obtained directly from the overall survival and disease-free survival curves in the 9735 study; life-years beyond 7 years were estimated using the average life expectancy of age-matched women in the general Canadian population. Canadian-specific resource utilization and unit costs (in 2008 Canadian dollars) were applied to estimate costs for chemotherapy administration, chemotherapy-related toxicities, recurrence, and adverse events. Health-utility scores and decrements used in the calculation of quality-adjusted life-years were derived from the literature. Results: The lifetime cost per quality-adjusted life-year gained was $8,251 for TC compared with AC, and the cost per life-year gained was $6,842. The results were robust across a range of sensitivity analyses. Conclusions: Cost-effectiveness, combined with efficacy and an acceptable safety profile, support the adoption of TC as an alternative to AC in Canadian clinical practice for the adjuvant treatment of operable early breast cancer.