HRT Raises Risk for Specific Breast Cancers

THURSDAY, Feb. 16 (HealthDay News) -- When taken for more than five years, estrogen-progestin hormone replacement therapy (HRT) is associated with a more than two-fold higher risk of lobular breast cancer or tubular breast cancer, compared with the more common ductal breast cancer, Swedish researchers report.
According to the American Cancer Society, about two-thirds of breast cancers are ductal malignancies, arising in the breast ducts. A smaller percentage of breast cancers are categorized as either lobular -- arising in milk-producing glands called lobules -- or tubular, meaning the cancer itself produces small glands and tubules resembling mammary ductules. Lobular and tubular breast cancers usually have a somewhat better prognosis than ductal cancers.
Reporting Thursday in the journal Breast Cancer Research, researchers at the Karolinska Institut in Stockholm found that HRT, typically given to help reduce menopausal symptoms, is associated with a greater risk of developing tubular rather than ductal cancer. The study also confirms previous findings that the therapy is associated with a greater risk of lobular cancer vs. ductal cancer.
The study included 1,888 women with ductal cancer, 308 women with lobular cancer, and 93 women with tubular cancer. They were matched with a control group of more than 3,000 women without breast cancer.
Both the breast-cancer patients and the women in the control group provided information on their medical history, health status and use of menopausal therapies.
Women who used medium potency estrogen-progestin combination therapy had a higher risk of either lobular or tubular breast cancer than of ductal cancer, compared with women who did not use hormone therapy. Women who used the therapy for more than five years had a higher risk, the study authors found.
They also found that other factors, such as body mass index, number of births, and age at menopause, were associated with a similar risk of developing these three forms of breast cancer.

More information
The U.S. National Heart, Lung, and Blood Institute has more about estrogen-progestin therapy.
Last reviewed: 02/16/2006 Last updated: 02/16/2006