A recent report from the San Antonio Breast Cancer Symposium showed that estrogen only use in postmenopausal women reduced the incidence of breast cancer. The information is based on further analysis of the Women’s Health Initiative ( WHI ) trial, and in fact, this finding was reported in 2004, two years after the initial publication from the trial, but received very little publicity at that time. The message in 2002 was that HRT had been shown to have significant risks and that the risks may outweigh the benefits. Almost overnight, the confidence in the use of HRT was lost, such that many women stopped taking HRT and many doctors stopped prescribing.
So why now the complete turn around according to information from the same study?
The results reported in 2002 were from the whole age range of women in the trial, who were aged between 50 and 79 years and these women had taken combined HRT (estrogen plus progestogen) or placebo. The highly publicised risks, which included increased risk of breast cancer, were in fact very small and when different age groups were later reviewed, the risks of combined HRT for women under 60 years, who are most representative of women who generally take HRT for symptom control, were minimal and for most of these women, combined HRT provided more benefits than risks. The risk of breast cancer in this group was increased only if women had taken combined HRT before the trial, and then for the 5 years of the trial and thereafter was of the order of 8 extra per 10,000 women per year.
This new report confirms the findings published in 2004 for the group of women in the trial who had had a hysterectomy and took either estrogen only HRT or placebo. In the women taking estrogen only, the risk of breast cancer was reduced, suggesting that estrogen alone acts differently on the breast compared to estrogen combined with progestogen. It could be suggested then that more women should be encouraged to take estrogen only HRT , but if the uterus is still present, some form of progestogen must still be given to prevent estrogenic stimulation of the lining of the uterus. Research and developments should now be focused on HRT which provides the benefits of estrogen on symptom control, bone protection and cardiovascular protection, while minimising the need for progestogen.
When considering the use of HRT, women and their doctors or nurses need to consider potential risks and benefits of HRT , and of different types. Balancing risks and benefits is not unique to HRT and takes place with the use of many medications. Other risk factors for breast cancer exist and include a history of breast cancer in mother or sister, paternal aunt or grandmother, increased breast density at mammograms, certain types of breast disease, obesity, alcohol and physical inactivity. Factors that reduce the woman’s risk of breast cancer include an early age of first full-term pregnancy, long-term breast feeding, exercise and no history of fibrocystic breast disease. These findings should be considered when prescribing or considering hormone therapy in postmenopausal women.
It is becoming very clear that the initial reports from the WHI trial exaggerated risks of HRT and that in fact for most women, when use appropriately, the benefits of HRT outweigh the risks, especially in women able to use estrogen only.
Commenting for the International Menopause Society, Professor David F. Archer, MD ( Norfolk , VA , USA ) said:
The re-analysis of the WHI data is reassuring to both women and physicians that women at low risk for breast cancer do not increase the incidence of breast cancer while using conjugated estrogen-only therapy. This finding supports the position of the International Menopause Society that any decision on the use of hormone therapy be based on an assessment of individual risks and benefits. These are different for each woman, and so the decision on hormone use should be taken after evaluating the risks and benefits, and subsequent discussions between a woman and her physician.
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