Hormone Therapy & Breast Cancer
Reported November 11, 2009
(Ivanhoe Newswire) Coinciding with the decline of postmenopausal hormone therapy in the U.S., the rate of atypical ductal hyperplasia, a known risk factor for breast cancer, has dropped by more than 50 percent.
Women who are diagnosed with atypical ductal hyperplasia — abnormal cells that grow in the milk ducts of the breast — are at a three- to five-fold increased risk of developing breast cancer.
“Postmenopausal hormone treatment is associated with increased rates of benign breast biopsies, and early and late stages of cancer. Atypical ductal hyperplasia is associated with the use of postmenopausal hormone treatment and its rates have decreased with the decline in use of this treatment,” researcher Tehillah Menes, M.D., who was the chief of breast service in the Department of Surgery at Elmhurst Hospital Center, New York, when this study was conducted, was quoted as saying.
Between 1996 and 2005, researchers found that postmenopausal hormone therapy use decreased from 35 percent to 11 percent. At the same time, atypical ductal hyperplasia decreased from 5.5 per 10,000 mammograms in 1999 to 2.4 in 2005. Cases of atypical ductal hyperplasia associated with cancer reached a peak of 4.3 per 10,000 mammograms in 2003, but decreased to 3.3 in 2005.
“The rate of atypical hyperplasia declined, which we didn’t expect to see with the increased use of mammography to identify abnormal lesions,” researcher Karla Kerlikowske, M.D., professor of medicine and epidemiology and biostatistics, University of California, San Francisco, was quoted as saying. “We did not expect to find a decline in rate of atypical ductal hyperplasia with a decline in postmenopausal hormone treatment use.”
Findings also showed that when atypical ductal hyperplasia is diagnosed with an associated breast cancer, the cancer is usually not an aggressive type. It is more often associated with low-grade cancers or those at early stage, providing evidence to support the theory of a separate pathway for development of low-grade and high-grade breast cancers, according to Menes.
Menes concluded, “These findings help clarify the different pathways to the development of breast cancer and the role of postmenopausal hormone treatment in increasing the rates of breast cancer.”
SOURCE: Cancer Epidemiology, Biomarkers & Prevention, November 9, 2009
