Cost-utility analysis is rapidly becoming the standard pharmacoeconomic measure in oncology. OBJECTIVE: To compare paclitaxel (pac) and docetaxel (doc) in the treatment of second line or greater metastatic breast cancer using a cost-utility analysis. METHODS: Utilities we collected from 45 patients using eight modified Markov modeled health states (Pharmacoeconomics, 1996; 60:504) describing metastatic breast cancer; the standard gamble procedure was utilized to obtain utility. Costs were collected prospectively from 31 patients in a single outpatient center. Direct medical costs were collected (e.g. all medications, physician/clinic/laboratory visits, ER, hospitalizations, home health care, consultations, special procedures, transfusions, phone calls, and miscellaneous) and costs were defined using Medicare reimbursement rates and AWP for drugs. Sensitivity analyses are currently underway. RESULTS: The average cost per cycle of chemotherapy was $4,298 and $2,869 for doc and pac respectively. The mean utility score obtained from patients was .78 and .76 for doc and pac respectively. The utility scores suggest that doc offers 7.3 days of perfect health when compared to pac. However, the incremental cost-utility analysis (cost of doc – cost of pac / QUALY of doc – QUALY of pac) indicates that the use of doc costs $71,450 per Quality Adjusted Life Year (QUALY) when compared to pac. Another way to view these results is that it costs $195.75 more per Quality Adjusted Day (QAD) to treat a patient with docetaxel. CONCLUSIONS: Our results indicate that docetaxel is more expensive ($4,298/cycle vs. $2,869/cycle) than paclitaxel, and that metastatic breast cancer patients do not perceive the drugs as being different (utility scores .76 for pac and .78 for doc). This cost-utility analysis suggests that the use of docetaxel over paclitaxel may not be justified in the treatment of metastatic breast cancer.