Hormone replacement therapy in prevention of morbidity and mortality in the older woman: part III: potential adverse effects of hormone replacement therapy

OBJECTIVES: The objective of this four part series is to review for the practicing clinician the extensive and sometimes contradictory literature on the effects of estrogen replacement therapy (ERT) and hormone replacement therapy (HRT) in the postmenopausal woman. This third article reviews HRT and the potential excess morbidity from breast cancer, endometrial cancer, venous thromboembolism (VTE), and coronary heart disease (CHD). DESIGN: Studies reviewed were obtained through Medline searches, examination of citations in the articles reviewed from those searches,interviews with local experts in geriatrics, cardiology, and women's health. CONCLUSIONS: Long-term HRT seems to be associated with a small increased risk for breast cancer. The risk of endometrial cancer in women with a uterus using ERT can be eliminated completely with the use of combination estrogen and progestin. HRT may be associated with a small increased risk for VTE; however, the absolute morbidity and mortality attributable to VTE is small and unlikely to impact the net benefit of HRT significantly. Although there is considerable data favoring a beneficial effect of HRT on CHD, initiation of HRT in women with established CHD may be associated with increased risk of adverse cardiac events in the first year after initiation. In counseling patients about the use of long-term HRT, the balance of these risks and the effect of co-morbid illness in the geriatric population should be addressed. Discussion of HRT and the aging brain (stroke, dementia), the net benefit of long-term HRT, and decision-making for the individual patient is forthcoming in the final article of this four-part series.