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

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.

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.

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).

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.