Estrogen replacement therapy in women with a history of breast cancer

Estrogens are known as potent mammary mitogen substances and are the major stimulus for the growth of hormone-dependent tumors and clearly implicated in the pathogenesis of breast cancer. Therefore it is a general belief that hormone replacement therapy (HRT) after breast cancer will increase the risk of developing recurrences, though there are no clear data available to support this suggestion. No prospective study with a large number of patients and a long treatment period was performed concerning this issue. On the other hand it may not be justifiable to withhold hormone replacement therapy from low-risk patients after menopause, knowing the benefits of this therapy concerning osteoporosis and cardiovascular advantages. Nevertheless, until appropriate clinical trials help to resolve this problem, non hormonal alternatives constitute the standard of care. One possible approach is to treat menopausal women who have had breast cancer symptomatically and avoid ERT unless absolutely necessary. The risk of cardiovascular diseases can be reduced with lifestyle. Tamoxifen has a beneficial effect on serum lipids and the intake for 5 years leads to a 50% reduction in the incidence of fatal myocardial infarction and a decrease in morbidity associated with ischaemic heart disease. Low doses of progestogen is effective for menopausal hot flushes. Tibolone reduces vasomotoric symptoms such as hot flushes and offers benefit on osteoporosis and has shown a significant reduction in high-density lipoprotein cholesterol. Whether replacing of estrogens is safe for patients after breast cancer remains uncertain. There is a need for a large controlled clinical trial to evaluate the safety and advantages of long time estrogen replacement in women treated for breast cancer.