Early study analysis suggests exemestane reduces breast density in high risk postmenopausal women

December 10, 2010

A drug that shows promise for preventing breast cancer in postmenopausal women with an increased risk of developing the disease, appears to reduce mammographic breast density in the same group of women. Having dense breast tissue on mammogram is believed to be one of the strongest predictors of breast cancer. The preliminary analysis from the small, phase II study was presented today at the 33rd Annual CTRC-AACR San Antonio Breast Cancer Symposium in Texas.

The ongoing study at Georgetown Lombardi Comprehensive Cancer Center and the Center for Cancer Research at the National Cancer Institute examines the effect of exemestane (Aromasin®) on breast density. Exemestane is in a class of medications called aromatase inhibitors (AI). It works by decreasing the amount of estrogen produced by the body. This can slow or stop the growth of some breast tumors that need estrogen to grow.

In this study, a preliminary analysis was conducted for the first 23 participants enrolled (42 women were enrolled as of June 2010). were taken before the women began exemestane and one year after treatment started. Breast density was compared between the two mammograms for each woman.

"Overall, we saw a seven percent decrease in mammographic density among the women, a statistically significant finding," says Jennifer Eng-Wong, M.D., M.P.H., assistant professor of oncology at Lombardi Comprehensive Cancer Center, a part of Georgetown University Medical Center. "Previous studies with AIs in high risk women have not shown a significant decline in mammographic density and differences in results may be due to duration of treatment or baseline characteristics of the study population."

She says earlier studies with tamoxifen, an FDA-approved drug to reduce breast cancer risk in women at high risk, also reduced breast density. A change in breast density appears to be an intermediate marker for breast cancer. For example a 10 percent drop in was correlated with a 50 percent drop in breast cancer incidence. Tamoxifen is in a different class of drugs. Side-effects of taking it have deterred women from choosing tamoxifen, resulting in a need for other treatment options such as aromatase inhibitors. In general, both of these agents are well tolerated, however rare serious side effects of tamoxifen include thrombo-embolic disease and endometrial cancer. The AIs are not associated with these side effects but have been associated with an increased risk of bone fracture and loss of bone density.

Women who were eligible for the study had an increased risk of breast cancer defined as one of the following: five year Gail model of risk ≥1.7 percent, a high risk breast lesion (e.g. lobular neoplasia or ductal carcinoma in situ), a known BRCA1/2 mutation, or a prior stage I/II with treatment completed two years prior to enrolling in the study. Women were excluded if testing revealed osteoporosis.

Eng-Wong points out that this stage of the analysis does not include a control group (women not taking exemestane) with whom the current findings could be compared, but she says a matched control comparison is planned. The study will continue until an analysis can be conducted on mammographic density after two years of treatment.

Related Stories

Recommended for you

New findings explain how UV rays trigger skin cancer

October 18, 2017
Melanoma, a cancer of skin pigment cells called melanocytes, will strike an estimated 87,110 people in the U.S. in 2017, according to the Centers for Disease Control and Prevention. A fraction of those melanomas come from ...

Drug yields high response rates for lung cancer patients with harsh mutation

October 18, 2017
A targeted therapy resurrected by the Moon Shots Program at The University of Texas MD Anderson Cancer Center has produced unprecedented response rates among patients with metastatic non-small cell lung cancer that carries ...

Possible new immune therapy target in lung cancer

October 18, 2017
A study from Bern University Hospital in collaboration with the University of Bern shows that so-called perivascular-like cells from lung tumors behave abnormally. They not only inadequately support vascular structures, but ...

Many pelvic tumors in women may have common origin—fallopian tubes

October 17, 2017
Most—and possibly all—ovarian cancers start, not in ovaries, but instead in the fallopian tubes attached to them.

Researchers find novel mechanism of resistance to anti-cancer drugs

October 17, 2017
The targeted anti-cancer therapies cetuximab and panitumumab are mainstays of treatment for advanced colorectal cancer, the second leading cause of cancer-related deaths in the United States. However, many patients have tumors ...

New bowel cancer drug target discovered

October 17, 2017
Researchers at the Francis Crick Institute have discovered a new drug target for bowel cancer that is specific to tumour cells and therefore less toxic than conventional therapies.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.