Research Finds Little Breast Cancer Risk in Estrogen

Most women who take a female hormone to diminish the symptoms of menopause or to prevent bone deterioration, strokes or heart attacks do not face an increased risk of breast cancer, a study says.

But researchers at the federal Centers for Disease Control in Atlanta found that women who had their ovaries removed and were undergoing estrogen replacement therapy had a slightly higher risk of developing the disease.

The risk doubled for those women if they were between 50 and 54 years old or if an immediate female relative had developed breast cancer, the researchers said.

“It’s important to emphasize that overall there was no significant increase” due to the use of estrogen, said Dr. Peter M. Layde, an epidemiologist for the centers and a co-author of the study.

Chance a Factor

“There was an increase in risk for some women who had had their ovaries removed, but some of that is chance and you would expect to see some cases,” Layde said. “We can’t rule out that part of the reason was estrogen replacement therapy.

“But the significance of this study is that . . . the number is probably not too great.”

The study, published in today’s Journal of the American Medical Assn., involved nearly 1,400 women with breast cancer and more than 1,600 randomly selected control subjects.

Prescribed Since 1960s

Estrogen, a female hormone produced by the ovaries, has been prescribed by doctors since the 1960s to control unpleasant symptoms of menopause, which marks the end of ovulation and the child-bearing years.

It also has been prescribed to adjust levels of the hormone in women who have had their ovaries removed.

More recently, estrogen has been used to prevent the wasting away of bones in post-menopausal women suffering from osteoporosis, which causes a general weakening of the bones, and cardiovascular disease.

Layde said the research was begun after several studies linked long-term estrogen replacement therapy to an increased incidence of breast cancer.