Because of treatment with chemotherapy, women with a history of breast cancer are more likely to be exposed to estrogen deficiency and often experience estrogen deficiency for a longer duration than women in the general population. Estrogen deficiency can cause hot flashes, vasomotor instability, genitourinary atrophy, cardiovascular disease, and osteoporosis.

Hormone replacement therapy (HRT)  is effective in the prevention and treatment of vasomotor instability, genitourinary atrophy, and osteoporosis.

However, there are concerns that HRT may increase the risk of coronary heart disease and stroke.

In addition, because breast cancer is believed to be a hormonally responsive disease, HRT is considered contraindicated in women with a history of this disease. Numerous nonhormonal alternatives are available to manage the symptoms of estrogen deficiency in breast cancer survivors.

Despite the general consensus that HRT is contraindicated in breast cancer survivors, preliminary evidence indicates that in carefully selected women successfully treated for localized breast cancer, HRT does not have a pronounced adverse effect on the rate of cancer recurrence and may be considered after appropriate patient counseling. Women diagnosed with breast cancer while receiving HRT have a better prognosis than do women diagnosed with breast cancer while not receiving HRT.

Introduction
Women with a history of breast cancer are more likely to be exposed to estrogen deficiency and may experience estrogen deficiency for longer durations than women in the general population. Chemotherapy, which is increasingly advocated for women with localized breast cancer as well as for women with advanced disease,  generally precipitates premature ovarian failure. In women with breast cancer or a history of this disease, hormone replacement therapy (HRT) is considered contraindicated as a matter of conventional practice because breast cancer is thought to be a hormonally responsive disease.  For these women,  then,  it is frequently necessary to delineate nonhormonal alternatives for management of problems linked to estrogen deficiency.

Consequences of Estrogen Deficiency
Ovarian estrogen production gradually declines after women reach the age of about 50 years. During the following decades, estrogen deficiency results in complex changes that characterize the menopausal years. Hot flashes and vasomotor instability are the most frequent and distressing symptoms and are the symptoms that most often motivate women to seek treatment.  Genitourinary atrophy may also occur;  this condition often leads to dyspareunia and may predispose patients to bladder infections. The most serious health hazard associated with estrogen deficiency is a progressive increase in the risk of cardiovascular disease,  which is the leading cause of death among older women. Estrogen deficiency also results in accelerated bone loss, leading to clinically significant osteoporosis in many women.  Osteoporosis is the most common metabolic bone disease in postmenopausal women and is responsible for more than one million hip fractures per year in the world.

In light of the long-term health hazards of estrogen deficiency,  the medical community has made a concerted effort to develop sensible and effective health-maintenance strategies for aging women,  using HRT as the principal intervention.

Gilbert G. Fareau and Rena Vassilopoulou-Sellin
Estrogen replacement therapy in breast cancer patients:  a time for change? Proc Am Soc Clin Oncol 1996;15:121.