(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
