Tamoxifen for breast cancer prevention: a framework for clinical decisions.

OBJECTIVE: Given the potential side effects and an uncertain survival benefit, decisions about tamoxifen treatment for the primary prevention of breast cancer remain complex. Primary care providers, including gynecologists, will need to counsel patients regarding this form of preventive care. In this report, we update cost-effectiveness calculations for tamoxifen chemoprevention and establish reasonable parameters for clinicians' use.
METHODS: We performed a cost-effectiveness analysis that compared women aged 50 years who were treated with tamoxifen for 5 years with an untreated cohort. In the base model, we assumed a 3.4% 5-year breast cancer risk. Quality-of-life estimates for important outcomes (breast cancer, endometrial cancer, deep venous thrombosis, pulmonary embolism, stroke, metastatic cancer, and hot flushes) were obtained from 106 women. Probabilities and costs of outcomes were derived from the Breast Cancer Chemoprevention Trial and other published estimates. Broad sensitivity analyses were performed. Cost per quality-adjusted life-year gained as a result of tamoxifen breast cancer prevention was the main outcome measure.
RESULTS: The use of tamoxifen led to a remaining life expectancy of 26.07 quality-adjusted life-years compared with 25.97 without treatment. The cost per quality-adjusted life-year gained was $43,300. Sensitivity analysis revealed that younger age, the absence of the uterus, higher initial risk of breast cancer, increased fear of curable breast cancer, and reduced tamoxifen cost further favored treatment.
CONCLUSION: Tamoxifen chemoprevention is cost-effective for women aged 40-50 years who are at significant breast cancer risk. Whether this holds true for older women depends on the initial breast cancer risk, fear of breast cancer, and presence of the uterus.