Hormone replacement therapy and breast cancer risk.

The role of estrogen therapy in the risk of breast cancer has been a concern for both physicians and patients. There is some evidence that women taking estrogen who develop breast cancer have a better prognosis. During 8 to 18 years of follow-up of 256 postmenopausal women with breast cancer from our hospital, median survival time was 84 months for those who never used estrogen, 80 months for past users, and 143 months for current users. More than 50 studies have shown that there is no increased risk of breast cancer even with long-term estrogen use, while some studies suggest an increased risk. Several studies indicate that when progestogens are added to estrogen therapy, there is a significant reduction in the risk of breast carcinoma. Indirect evidence is accumulating to show why added progestogen should decrease the risk of breast cancer. Preliminary studies further indicate that estrogen therapy, which has been contraindicated in breast cancer survivors in the past, may be safe, and added progestogens may decrease recurrences and deaths. Some medical oncologists and surgeons now advocate estrogen use in women with previous carcinoma of the breast.