Reduced incidence of distant metastases and lower mortality in 1072 patients with breast cancer with a history of hormone replacement therapy

Objective Substitution of estrogens (hormone replacement therapy [HRT]) is the most common therapy and prophylaxis of postmenopausal complaints. However, in most studies, long-term HRT has been associated with an increased risk for breast cancer, but the influence on a prognosis of breast cancer has been examined rarely. Study Design For further investigation, we analyzed 1072 patients aged 45-70 years at the time of first diagnosis of breast cancer with and without preoperative HRT with regard to the incidence of distant metastases and overall survival. Of these, 279 women were premenopausal (mean, 47.8 ± 3.2 years); 793 women were postmenopausal (mean, 54.5 ± 3.5 years); 320 women had received HRT over a minimum of 1 year (mean, 5.5 ± 4.0 years; group HRT+); and 473 women had not received HRT (group HRT−). The median follow-up time was 73.2 months. Results Although body mass index, tumor size, and grading of group HRT− were significantly higher than in group HRT+, nodal status, S-phase fraction, hormone-receptor status, and local recurrence showed no significant differences. In regard to the incidence of distant metastases, women without HRT have significantly ( P < .001) more metastases to bone (68 vs 20 women), lung (47:13 women), and liver (47:13 women). Overall survival was significantly lower in the HRT− group. Conclusion We were able to show that the use of HRT before the diagnosis of breast cancer results in more favorable primary tumors, with a lower incidence of recurrences and a better overall survival rate. This might be due to normalized bone metabolism by the use of HRT, which may lower the conditions of tumor cell seeding.