CLINICAL QUESTION: Is estrogen replacement therapy (ERT) beneficial for women after treatment for breast cancer?
BACKGROUND: A history of breast cancer is considered a contraindication for ERT, on the assumption that this treatment promotes carcinoma of the breast and may therefore hasten recurrences and metastases. However, evidence of this is lacking. The authors of this study challenged the assumptions.
POPULATION STUDIED: All women (N = 76) with a history of breast cancer seen in an academic practice from 1978 through 1998 were included. Age ranged from 34 to 83 years with a mean of 61.8 ± 2.6 years. Information regarding ethnicity was not provided.
STUDY DESIGN AND VALIDITY: This is a retrospective case series (chart review). The methods section of the paper consists entirely of a description of the Population studied and the fact that most of the information was obtained from charts and supplemented by the hospital tumor registry. Additionally, telephone calls were made to determine the current status of those women whose records had not been updated in the past year.
OUTCOMES MEASURED: The number and percentage of each group that died during the study period and the cause of death were the main results reported. The length of time each woman was receiving ERT was a secondary measure.
RESULTS: Of the women receiving ERT, 3 (6%) died: 2 of breast cancer and 1 of myocardial infarction. This group included the one patient with advanced disease at baseline. Of the women receiving nonestrogen hormone replacement therapy, one (12.5%) died of breast cancer. Of the group receiving no hormones, 6 (33.3%) died: 5 of breast cancer and 1 of a stroke. Mean duration of ERT was 5.5 ± 2.5 years, with a range of 6 months to 32 years.
It cannot be assumed that ERT is contraindicated for women who have been treated for stage I breast cancer. At this point, it is not known whether ERT has any influence on the prognosis of breast cancer. This study and several other observational studies cited by the authors suggest that it may even improve the prognosis. A well-designed randomized controlled trial of ERT after treatment for breast cancer is warranted. Definitive results will take many years to obtain. In the meantime, individual patients previously treated for breast cancer should be counseled regarding what is known about the risks and benefits of ERT and should be given the option of using it.