Estrogen replacement therapy in breast cancer survivors: a matched-controlled series.

Objective: We prospectively administered estrogen replacement therapy (ERT) to control estrogen deficiency symptoms in breast cancer survivors as part of our clinical practice. We report the consequences of ERT compared with a historical matched-control group.

Design: Two hundred seventy-seven disease-free survivors received ERT. Controls were matched for exact stage, a recurrence-free period similar to the period to ERT initiation in the ERT group, approximate age, and duration of follow-up. The mean time from breast cancer diagnosis to initiation of ERT was 3.61 (+/- 0.25) years, with a median of 1.88 years. The mean duration of ERT was 3.7 (+/- 3.01) years, with a median of 3.05 years.

Results: Hot flashes were relieved in 206 of 223 women (92%), dyspareunia/vaginal dryness in 149 of 167 women (89%), and reactive depression/anxiety/mood change in 111 of 126 women (88%). Univariate analysis demonstrated no statistical differences between the groups for age, stage, pathology at diagnosis, progesterone receptor status, local therapy, breast at risk, prior chemotherapy, and duration of follow-up. The ERT group was more likely to be estrogen receptor negative (P = 0.01), to have received prior ERT (P < 0.001), and to have received no adjuvant tamoxifen (P < 0.001). There was no significant difference between the ERT and control groups in ipsilateral primary/recurrence (5/155 v 5/143; P = 0.85), contralateral breast cancers (10/258 v 9/260; P = 0.99), or systemic metastasis (8/277 v 15/277; P = 0.13). Noncause-specific deaths in the control group numbered 15 (of 277), and in the ERT group, 7 (of 277) (P = 0.03). Overall survival favored the ERT group (P = 0.02).

Conclusions: In these selected patients, ERT relieved estrogen deficiency symptoms and did not increase the rate or time to an ipsilateral recurrence/new primary, contralateral new primary, local-regional recurrence, or systemic metastases.