SAN ANTONIO--Three studies reported at the San Antonio Breast Cancer Symposium show no apparent adverse effects of hormone replacement therapy (HRT) on breast cancer and, in fact, suggest that breast cancers in patients with a history of HRT may have a more favorable prognosis in terms of histologic grade and estrogen-receptor (ER) levels.
The largest study focused on 432 postmenopausal women diagnosed with invasive breast cancer at University Hospital of South Manchester, England--109 with a history of HRT (mean duration, 48 months) and 323 who had never received hormones. To qualify as HRT users, patients must have used HRT for at least 3 months and within 3 months of the cancer diagnosis, said surgical oncologist Claudia Harding.
Tumors in the two patient groups were similar with respect to nodal involvement, tumor size, and ER status. However, women who received HRT had significantly more grade 1 tumors (42% vs 24%). A subanalysis showed that women who had taken hormones for more than 2 years were significantly more likely to have ER-positive tumors.
"HRT is associated with better grade, and better grade is associated with improved prognosis," Dr. Harding said. "Thus, HRT does not appear to have an adverse effect on mortality." She added that the similarity with respect to tumor size and node status reflected that the women all had asymptomatic disease that was detected by screening.
Higher ER Levels
A Cincinnati study showed that hormone users develop tumors with significantly higher ER levels. Researchers evaluated the history of hormone use (contraceptives, fertility drugs, and conjugated estrogens(Drug information on estrogens)) in 128 premenopausal and 197 postmenopausal women with breast cancer. Overall, 102 patients had never used hormones for any purpose. Their breast tumors had a mean ER level of 51 fm/mg and a progesterone(Drug information on progesterone) receptor (PR) level of 92.9 fm/mg.
By comparison, the 223 patients with a history of hormone use had tumors with a significantly higher ER level, averaging 79.2 fm/mg, and similar average PR level (107.9 fm/mg), reported Elyse Lower, MD, associate professor of medicine, University of Cincinnati.
Separate analyses of pre- and post-menopausal women showed no significant correlations between hormone use and receptor levels of tumors. Dr. Lower suggested that higher ER content might account for previous reports that post-menopausal hormone users develop tumors with a more favorable prognosis.