QUESTION: I'm a postmenopausal woman and I understand that a new study shows estrogen does not increase breast cancer risk after all. Is this really true?
ANSWER: That seems to be the case, and it's certainly good news. This latest finding was hinted at in prior research, so it was not totally unexpected.
We'll get to the details in a minute. First, let's cover some estrogen basics.
Levels of natural estrogen fall after menopause. Estrogen-replacement therapy helps relieve menopausal symptoms such as hot flashes.
Estrogen-only therapy can be used in women without a uterus. Estrogen-progestin therapy is used in women with a uterus because the progestin counters the estrogen-related increased risk of endometrial cancer.
The most feared drawback of estrogen therapy has been the apparent increased risk of breast cancer associated with it.
A prior placebo-controlled clinical trial evaluated both estrogen-only therapy and estrogen-progestin therapy in postmenopausal women. It found that combination estrogen-progestin therapy did boost breast cancer risk over about five years of treatment. In contrast, preliminary evidence suggested that estrogen-only therapy might reduce the risk of breast cancer.
Before that clue could be scrutinized, the estrogen-only part of the trial was prematurely halted because of a higher risk of stroke in those taking estrogen. However, the tantalizing possibility that estrogen-only therapy could actually reduce breast cancer risk prompted researchers to go back and carefully comb over the estrogen findings. This follow-up constitutes the “new study” that's been in the news.
The estrogen-only part of the study covered 10,739 postmenopausal women (with prior hysterectomy) ages 50 to 79. One group took estrogen and one group took a placebo. In summary, researchers found that estrogen therapy did not appear to increase the risk of breast cancer, and may have reduced the risk of early-stage disease during the seven-year treatment period.
This is an early take on the results, and more information is likely to be forthcoming.
These are welcome findings, and women who take estrogen-only therapy can breathe a little easier in regard to breast cancer. Even so, an increased risk of stroke, leg blood clots, and heart-related adverse effects are still a concern with hormone therapy. Older age and longer treatment time appear to amplify the risks.
Though estrogen replacement therapy helps prevent postmenopausal osteoporosis, most clinicians think it should not be prescribed solely for that purpose.
So the rationale for prescribing hormone therapy remains whittled back to its roots: to relieve severe menopausal symptoms such as hot flashes, vaginal dryness, night sweats and sleep disturbances. No other treatment works as well.
When hormone therapy is prescribed, the lowest effective dose should be used and treatment can be stopped once symptoms subside. Newer formulations of low-dose estrogen in pill and skin patch form appear to work about as well as standard doses, but with less risk.
Richard Harkness is a consultant pharmacist and specialist in natural therapies. E-mail:
rharkn@aol.com.
