Estrogen replacement therapy after breast cancer: A 12-year follow-up

Background: In the United States, estrogen replacement therapy (ERT) is discouraged in breast cancer survivors because of concerns that hormones may reactivate the disease. Because ERT can improve quality of life and decrease morbidity from osteoporosis and cardiovascular disease, however, this policy is increasingly being challenged. Methods: From February to August 1995, 607 breast cancer survivors were interviewed concerning ERT usage. Sixty-four patients indicated they received some form of ERT after their breast cancer diagnosis. Medical records for these patients were analyzed for disease stage, surgical treatment, adjuvant treatment, estrogen and progesterone receptor status, date of initiation of ERT, type of ERT, recurrence, and final outcome. Patients receiving ERT were followed prospectively. Results: Eight patients were excluded because they had used only vaginal cream ERT. The remaining 56 received ERT as conjugated estrogens, an estradiol patch, estropipate, or birth control pills. The median follow-up from diagnosis was 12.8 years (range, 4.7-38.9 years). The median time on ERT since diagnosis was 6.4 years (range, 1.0-20.9 years); 38% of the patients initiated ERT within 2 years of diagnosis. Estrogen receptors were positive in 28 (74%) of the 38 cases with available information. Pathological disease stage at time of diagnosis and treatment was 0 in 15 cases (27%), I in 27 (48%), and II in 14 (25%). Twenty-six patients (47%) received adjuvant chemotherapy or hormonal therapy. One local recurrence and one contralateral breast cancer occurred during the follow-up period (13.5 and 9,6 years, respectively), with no regional or distant recurrences, for a 15-year actuarial disease-free survival rate of 92.5%. There were no breast cancer deaths. Conclusions: Use of ERT in a cohort of breast cancer survivors with tumors of generally good prognosis was not associated with increased breast cancer events compared with non-ERT users, even over a long follow-up period.