Outcomes of Tamoxifen Chemoprevention for Breast Cancer in Very High-Risk Women: a Decision Analysis

D.L. Hershman, V. Sundararajan, J. Jacobson, A. Neugut, V. Grann; Columbia University, New York, NY; Monash University, Melbourne, Australia

In 1998, the NSABP reported that in its Breast Cancer Prevention Trial, treatment with tamoxifen decreased the risk of invasive breast cancer by 49%. Subset analyses suggest that tamoxifen might be especially beneficial for women with very high risk due to atypical ductal hyperplasia, lobular carcinoma, in situ, Gail risk 5, or 2 first-degree relatives diagnosed with breast cancer.

Using a Markov model, we estimated the survival, quality-adjusted survival, and cost-effectiveness benefits of tamoxifen treatment in these very high risk groups. Our model incorporated risks of breast cancer from the NSAPB trial; survival data from SEER; quality adjustment from a time trade-off questionnaire, costs for hospital and ambulatory care from the Group Health Cooperative of Puget Sound and the HCFA; and drug costs from Pharmacy Fundamental Reference. Among women like BCPT participants overall, our model indicated that initiating therapy at ages 35, 50 and 60, would prolong survival by 69, 40 and 27 days respectively. Women who initiate tamoxifen treatment at age 35 would obtain the greatest benefit. In the very high-risk subgroups, the model projected substantially greater benefits.

In conclusion, using decision analysis for subgroups of women at elevated risk for breast cancer, we have shown substantial benefits in survival, quality-adjusted survival and cost -effectiveness when tamoxifen is used as a chemopreventative agent. These benefits are significantly greater for women who are at very high risk for breast cancer and when tamoxifen use is initiated at an earlier age.

Benefits and costs of initiating tamoxifen at age 35 years