Elements of informed consent for hormone replacement therapy in patients with diagnosed breast cancer.

Abstract

An approach to providing informed consent to breast cancer survivors considering hormone replacement therapy (HRT) is offered. Current information on HRT, breast cancer, and chronic disease prevention is reviewed in the context of risks faced by women with resected breast cancer. Breast cancer patients, unwilling to trade symptom reduction for even a small increase in recurrence risk, are at substantially increased risk of death from breast cancer relative to other causes. Observational studies suggest that long-term HRT increases breast cancer development. The influence of HRT on the growth of established breast cancer has not been determined; however, estrogen reduction (oophorectomy) significantly reduces recurrence in premenopausal women, and current evidence cannot exclude a risk that HRT increases recurrence to the same degree. The following issues are of particular relevance to breast cancer survivors: HRT reduces mammographic sensitivity, increases thromboembolic events, and increases endometrial cancer risk. Although benefit for HRT is commonly inferred from observational studies, randomized trials of HRT on all-cause mortality have not been completed. For coronary heart disease prevention, an array of strategies independent of HRT are available, with some (tamoxifen, selective estrogen receptor modifiers [SERMs], diet, and exercise) likely to favorably influence breast cancer risk; for osteoporosis prevention, an array of strategies also are available, with some (bisphosphonates, tamoxifen, SERMs, and exercise) likely to favorably influence breast cancer risk. Current data preclude the generation of evidence-based guidelines for HRT use in breast cancer survivors, and clinical trials in this setting should be supported. However, given available therapeutic alternatives for menopausal symptom management and chronic disease prevention, breast cancer survivors should be offered HRT only with caution and with their full participation in the decision-making process.