Estrogen therapy may affect mammograms, study says
May 15, 1996
Web posted at: 3:45 p.m. EDT
From Correspondent Jeff Levine
WASHINGTON (CNN) -- Estrogen replacement treatment may reduce the ability of mammograms to detect breast cancers because it thickens breast tissue, a new study says.
But doctors warn that the therapy merely can make it harder to read a mammogram, and women shouldn't necessarily stop taking estrogen.
For many women, taking replacement hormones after menopause smoothes the process of aging, while for others it's a medical necessity. Now there's a new study that shows taking estrogen could cause a false reading on a mammogram.
Normally, breast tissue becomes less dense with age as it turns more fatty, making it more transparent to mammography. But estrogen treatment reverses the effect.
Cancer appears as a white spot on a mammogram, making the disease harder to detect on a breast with denser tissue, said Dr. Mary Laya of the University of Washington-Seattle, where the study was done. (155K AIFF or WAV sound) Results were published in the Journal of the National Cancer Institute.
The five-year survey of mammography and hormone treatment covered nearly 9,000 women 50 years of age and older.
Among women taking the hormone, there was a one-third higher false-alarm rate for cancer compared to women who had never used, or formerly used, estrogen therapy. Researchers said in a small number of cases the cancer was missed completely.
The results suggest more study is needed on a treatment linked to important benefits and a few liabilities.
In addition to its negative effect on mammography, estrogen replacement also has been suggested as a source of breast cancer, although the correlation has not been proven.
Estrogen a benefit
In estrogen's favor, the treatment can reduce dangerous thinning of the bones in elderly women and appears to prevent heart disease.
In the eyes of Dr. Safa Rifka with the Columbia Hospital for Women, the most important benefit is protection against heart attacks. (95K AIFF or WAV sound)
The result of this study on estrogen replacement therapy is that women need to be aware of the increased difficulty in reading their mammograms; they shouldn't stop taking estrogen, cautions Dr. JoAnne Zujewski of the National Cancer Institute. (115K AIFF or WAV sound)
Health professionals say it's a complicated issue best resolved between a woman and her doctor.
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