(WOMENSENEWS)–Of the estimated 3 million women who take combined hormone therapy, about 120,000 of them may have abnormal mammograms solely due to their hormone treatment, reports a new study done by the Women’s Health Initiative just published in the Journal of the American Medical Association.

In the new study, researchers report that the use of estrogen plus progestin hormone treatments “significantly increases the incidence of breast cancer” and that the combination also delays breast cancer diagnosis by making the tumors more difficult to detect, leading to increases in tumor size and severity when detected.

Once marketed as a necessity for women going through menopause, hormone therapies have recently been found to increase the risk of other serious diseases including blood clots and Alzheimer’s Disease.

In an editorial accompanying the report, Dr. Peter H. Gann and Dr. Monica Morrow of Northwestern University said: “The message for physicians caring for menopausal patients is clear” and that the results “provide further compelling evidence against the use of combination estrogen plus progestin hormone therapy.”

Natalie de Vane, a spokeswoman for Wyeth, makers of the popular hormone replacement therapy brand Prempro, told The New York Times that the new data is “clearly important for women to know” but that hormones such as Prempro are necessary because they are the only products out there to treat severe menopausal symptoms. She projects that sales of Wyeth’s hormone products will total $1.5 billion this year and that the sales will not be changed by the recent findings.

— Samantha Xu.

For more information:

Women’s Health Initiative–
WHI Findings Summary
“Estrogen plus Progestin Effects on Breast Cancer and Mammograms”: