One type of hormone therapy - oestrogen plus progestin - already is well-known to increase the risk of breast cancer. But a major US study of women able to use oestrogen alone did not find that link.
Researchers have now reported a new wrinkle: those oestrogen-only users doubled their chances of getting non-cancerous breast lumps. That's a concern not only because of the extra biopsies and worry those lumps cause, but because a particular type - called benign proliferative breast disease - is suspected of being a first step toward developing cancer 10 years or so later.
About one in five US women undergo a breast biopsy within a decade of starting annual mammograms, and most are of those abnormalities turn out to be benign.
Yet under a microscope, there are different types, from simple fluid-filled cysts to what is called proliferative breast disease because it's made of growing cells.
Study re-examines previous data
The latest work, published in the Journal of the National Cancer
Institute, re-examines data from the landmark Women's Health Initiative that found a variety of health risks from long-term hormone therapy.
Only women who have undergone hysterectomies are able to use oestrogen-only therapy, and the initiative originally included more than 10 000 of those women, who were given either oestrogen or a dummy drug and tracked for about seven years.
Now, a team led by Dr Tom Rohan of the Albert Einstein College of Medicine in New York has reviewed breast biopsies done on those women - and identified 232 cases of benign proliferative breast disease.
Women given the oestrogen-only therapy had twice the risk of developing these abnormalities compared with women given a placebo.
Study participants are still being tracked, allowing scientists to eventually tell if the benign breast problems were a signal of more trouble to come, Rohan concluded. – (Sapa)
April 2008
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