The natural production of estrogen declines after menopause, causing side effects such as hot flashes, vaginal dryness and loss of bone density. Hormone replacement therapy restores a woman's hormonal balance and relieves menopausal symptoms, but the added estrogens can promote tumor growth in certain hormone-dependent cancers.
Premarin
Premarin is the brand name for a preparation of estrogen synthesized from the urine of pregnant mares, according to the National Heart, Lung, and Blood Institute. Premarin is a hormone replacement therapy, primarily used to relieve menopausal symptoms.
Estrogen and Breast Cancer
The female hormone estrogen promotes the growth of breast and uterine tissue. This natural function of estrogen also stimulates the growth of certain types of hormone-dependent breast cancers. Approximately three quarters of all breast cancers are estrogen receptor positive (ER-positive), which means estrogen causes these tumors to grow. The tumors do not distinguish between estrogen produced naturally and hormones ingested in replacement therapies.
Premarin and Breast Cancer
The Women's Health Initiative (WHI), a large-scale study of the effects of hormone replacement therapy in postmenopausal women, found Premarin was associated with slightly fewer cases of breast cancer compared with placebo. Estrogen alone was associated with less breast cancer than combined estrogen and progesterone hormone replacement therapy, according to the National Cancer Institute (NCI). The reduced risk associated with Premarin was seen only in women who had had a hysterectomy, and the reduction was only for early stage breast cancer and cancer of the lining of the milk ducts.
The decrease in breast cancer incidence was not statistically significant, meaning the findings could have been due to chance. A combined analysis of the results of 51 studies of hormone replacement therapy found any type of hormone replacement therapy, even estrogen alone, increased a woman's risk for breast cancer, according to the NCI. In these combined studies, the majority of women (88 percent) used estrogen alone. The rate of breast cancer increased the longer hormone replacement therapy was taken and with higher doses.
Recommended Use
Premarin is recommended only for women who have had a hysterectomy for relief of menopausal symptoms. It is not recommended only for the prevention of osteoporosis, however. Premarin should be used at the lowest effective dose for the shortest duration possible.
Cautions
Women should not take Premarin if they have a history of breast or uterine cancer. While taking Premarin, women should receive regular exams and they should perform breast self-exams monthly. Premarin use may increase the chance of an abnormal mammogram. Common side effects associated with Premarin include breast swelling, tenderness and pain. Long-term use of Premarin may lead to an increased risk of breast cancer, heart attack and stroke.
Tags: replacement therapy, hormone replacement, associated with, breast cancer, hormone replacement therapy, breast cancer
