Long-term
estrogen therapy linked to breast cancer risk

A new study in the Archives of Internal Medicine continues to add to the mounting evidence of the health risks of hormone replacement therapy for menopausal and postmenopausal women. The new study shows that women who take estrogen pills for 15 years or more have a dramatically higher risk of developing breast cancer than women who take the drug less than 10 years or don't take estrogen pills at all. The researchers say their findings suggest that estrogen may be useful for menopausal women to use in the short term to control such symptoms as hot flashes and vaginal dryness but that long-term use should be discouraged.

Previous studies have linked estrogen-progestin combination hormone replacement therapy to significantly higher risks for breast cancer, heart attacks, and strokes. Prior research also linked estrogen-only therapy with an increased risk of strokes and memory problems, but not breast cancer. Estrogen-only therapy also has been linked with the development of uterine cancer, and as such it is typically prescribed only to postmenopausal women who've had their uterus removed.

The newest study, based on data collected from nearly 29,000 women, showed that those who took estrogen-only hormone replacement therapy for at least 15 years had a 48% greater risk of developing hormonally driven breast cancer, the most common form of the disease in the United States. After 20 years of treatment, the risk of any type of breast cancer climbed by 42%, according to the study.

"This says, at least for the shorter-term users, you don't need to panic" about breast cancer, said lead author Wendy Chen to the Associated Press. Chen--who is an oncologist and epidemiologist at Brigham and Women's Hospital and the Dana-Farber Cancer Institute, both in Boston--noted, "But for the longer-term users, you need to think about, Why am I still taking estrogen for this long a time, and are there are alternatives I could take instead?" (The Advocate)