Drug Combination May Slow Male Breast Cancer Growth

Male Breast Cancer

Medical oncologists across the nation want to know whether a certain drug combination can slow the progression of male breast cancer, a rare disease that often goes undiagnosed until it's in an advanced stage.

Zeina Nahleh, MD, director of breast oncology in the University of Cincinnati's (UC) division of hematology and oncology, is leading a national phase-2 clinical trial to test whether the drug anastrozole (Arimidex), currently approved by the Food and Drug Administration (FDA) for treating breast cancer in postmenopausal women, can effectively fight the same disease in men.

"If we're going to make significant advances against the disease," says Nahleh, "we need better male-specific treatment strategies."

Previous research has shown that the female hormone estrogen promotes the growth of certain types of breast cancer. Anastrozole is one of a class of drugs, known as non-steroidal aromatase inhibitors, that block the tumor's use of estrogen and slow its development.

By treating male breast cancer with a combination of anastrozole and a synthetic hormone called goserelin, Nahleh believes physicians may be able to stop the transition of the male hormone testosterone to the estrogen estradiol, significantly lowering the man's overall estrogen levels and limiting breast tumor growth.

Goserelin is what is known as a gonadotropin-releasing hormone, which stops testosterone production in men and decreases estradiol in women. It already has FDA approval for the treatment of prostate cancer, endometriosis and advanced premenopausal and perimenopausal breast cancer.

"The biology of breast cancer is different in men and women, so identical treatment methods are not the best solution," explains Nahleh. "We believe that anastrozole - when used in conjunction with a gonadotropin-releasing hormone injection - will lower the amount of male estrogen in the body, resulting in better control of the breast tumor."

The trial, sponsored by the National Cancer Institute and Southwest Oncology Group, is the first to test this specific drug combination in men with advanced breast cancer.

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