Drug Combination May Slow Male
Breast Cancer Growth
Behind the
Cancer Headlines®
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.
“We’ve seen a 26 percent increase in the number of male
breast cancer cases since 1973, but the disease is so rare that there’s been
little research to determine the best ways to detect and treat the disease
specifically in men,” explains Nahleh.
Current male breast cancer treatment methods are based on
accepted approaches to the disease in women. Unlike female breast cancer, says Nahleh, the relationship between the estrogen receptor and
overall survival in men is uncertain. In addition, mortality from the disease
has not declined as it has in women.
Under Nahleh’s direction,
researchers from 53 medical centers nationwide will test the drug combination
on about 60 male patients—age 18 or older—who have recurrent or advanced breast
cancer.
Patients will receive an anastrozole
pill every day and a goserelin injection on the first
day of 12, month-long cycles. Every two months researchers will collect serum
samples to evaluate blood estrogen levels. They will also obtain CAT scan and
X-ray images of the tumor to determine how the patient is responding.
After the treatment, Nahleh and
her team will follow patients for three years to determine whether the approach
is a sustainable option for managing male breast cancer.
The American Cancer Society estimates that more than 1,700
men will be diagnosed with breast cancer in 2006 and about 27 percent will die
from the disease.
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