If estrogen stimulates the growth of malignant breast cells, one might be concerned that subclinical disease may be fueled by HRT and grow rapidly, resulting in a worse clinical outcome. We have no information on the outcome of recurrent disease in women who begin HRT after having been treated for breast cancer.
In the general population, however, the hypothesis that HRT could result in more aggressive disease has been the subject of several studies, all of which have provided reassuring evidence that the prognosis of women who are taking HRT when they are initially diagnosed with breast cancer is similar to, if not better than, the prognosis of women who are not receiving HRT when they are initially diagnosed with breast cancer.
HRT appears to beneficially influence the biological characteristics of breast tumors (Squitieri et al., 1994; Harding et al., 1996; Magnussom et al., 1996; Bonnier et al., 1998; Gapstur et al., 1999).
Breast tumors diagnosed in women receiving HRT behave less aggressively than other breast tumors (Holli et al., 1998; Bergkvist et al., 1989; Strickland et al., 1992), and overall mortality from breast cancer in women receiving HRT at diagnosis has been reported to be either unchanged (Yuen et al., 1993; Fowble et al., 1999; Hunt et al., 1990; Jernstrom et al., 1999) or improved (Willis et al., 1996; Schairer et al., 1999; Sellers et al., 1997; Hormone Foundation et al., 1998) compared to mortality in women not receiving HRT at diagnosis.
It is possible that the improved outcome of HRT recipients is due to a combination of a health-conscious lifestyle, including conscientious screening, plus a favorable effect of HRT on the biology of the disease.
Many menopausal women, including breast cancer survivors, experience mild and self-limited climacteric symptoms but, by virtue of their individual health profiles, are not at risk for heart or bone disease. For these women, no medical interventions are needed. Other women have an increased risk of heart disease or osteoporosis but not both. For some women, climacteric symptoms are overwhelming and overshadow all other considerations.
The therapeutic decisions in these various potential scenarios must be individualized.
At M. D. Anderson, we believe that appropriate nonhormonal measures should be carefully and vigorously explored as a first approach to relief of menopausal symptoms in breast cancer survivors. However, if climacteric symptoms or skeletal and cardiovascular morbidity compromise a patient’s health or quality of life, estrogen use may be considered in the context of clinical trials or after thoughtful, individualized discussion.
- 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.
- The risk of CHD appears to increase with use of estrogen plus progesterone, but it is unclear if estrogen use alone has the same effect. HRT has been shown to increase the risk of thromboembolic disease.
- The evidence no longer favors the routine use of HRT in the treatment of menopause. Many alternative approaches are available to correct or palliate the sequelae of estrogen deficiency.
- HRT remains the most effective agent for the treatment of vasomotor and other climacteric symptoms, and if a woman is unable to find relief from disabling symptoms with alternative therapies, a joint decision between the physician and the informed patient to prescribe HRT remains a reasonable course of action.
- In the absence of definitive safety data, we continue to counsel our patients that a history of breast cancer remains a relative contraindication to HRT; we particularly discourage patients with recently treated, extensive, or hormonally responsive disease from using HRT.
- The prognosis of women who are taking HRT when they are initially diagnosed with breast cancer is similar to, if not better than, the prognosis of women who are not receiving HRT when they are initially diagnosed with breast cancer.
- If climacteric symptoms or skeletal morbidity compromise a breast cancer survivor’s health or quality of life, estrogen use may be considered in the context of clinical trials or after thoughtful, individualized discussion.
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.