The cost-utility of adjuvant chemotherapy using docetaxel and cyclophosphamide compared with doxorubicin and cyclophosphamide in breast cancer

PURPOSE

The adoption of a chemotherapeutic regimen in oncologic practice is a function of both its clinical and its economic impacts on cancer management. For breast cancer, U.S. Oncology trial 9735 reported significant improvements in disease-free and overall survival favoring adjuvant tc (docetaxel 75 mg/m(2) and cyclophosphamide 600 mg/m(2) every 3 weeks for 4 cycles) compared with ac (doxorubicin 60 mg/ m(2) and cyclophosphamide 600 mg/m(2) every 3 weeks for 4 cycles). We carried out an economic evaluation to examine the cost-utility of adjuvant tc relative to ac, in terms of cost per quality-adjusted life year (qaly) gained, given the improved breast cancer outcomes and higher costs associated with the tc regimen.

METHODS

A Markov model was developed to calculate the cumulative costs and qalys gained over a 10-year horizon for hypothetical cohorts of women with breast cancer treated with ac or with tc. Event rates, costs, and utilities were derived from the literature and local resources. Efficacy and adverse events were based on results reported from U.S. Oncology trial 9735. The model takes a third-party direct payer perspective and reports its results in 2008 Canadian dollars. Costs and benefits were both discounted at 3%.

RESULTS

At a 10-year horizon, tc was associated with $3,960 incremental costs and a 0.24 qaly gain compared with ac, for a favorable cost-utility of $16,753 per qaly gained. Results were robust to model assumptions and input parameters.

CONCLUSIONS

Relative to ac, tc is a cost-effective adjuvant chemotherapy regimen, with a cost-effectiveness ratio well below commonly applied thresholds.