Class of Chemotherapy Drugs Helps Certain Breast Cancer Patients

By Kathleen Doheny
HealthDay Reporter
Wednesday, December 26, 2007; 1:00 PM

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WEDNESDAY, Dec. 26 (HealthDay News)-- Chemotherapy drugs known as anthracyclines help boost survival for women with HER2-positive breast cancer who have undergone surgery, but they may not offer any survival benefit for those with HER2-negative tumors.

That's the conclusion of a wide-ranging analysis that pooled the results of eight randomized trials that compared the drugs with non-anthracyclines and took into account the women's HER2 status.

HER2-positive cancers test positive for a protein called human epidermal growth factor receptor 2 (HER2) and tend to grow quickly, the researchers said.

Since anthracyclines (such as doxorubicin and epirubicin) were introduced in the 1980s, they have been widely used as supplementary chemotherapy for breast cancer, said Dr. Alessandra Gennari, a medical oncologist at the National Cancer Research Institute in Genoa, Italy, and lead author of the study.

But the new analysis may change that, Gennari said. "Our study provides convincing statistical evidence that the added benefit of adjuvant chemotherapy with anthracyclines is confined to women who have breast tumors in which HER2 is overexpressed or amplified," she said.

"Since only about 25 to 30 percent of all breast cancers are HER2-positive, the vast majority of patients, with HER2-negative disease, may be spared unnecessary toxicities related to the use of this class of agents," she added.

The study findings were published online Dec. 25 in the Journal of the National Cancer Institute.

Anthracyclines have been associated with an increased risk of heart damage in some patients -- a risk doctors have known about for some time. An increased risk of leukemia, which can strike years later, is also associated with use of the drugs.

But, Gennari said, anthracyclines came into widespread use despite these risks, because a previous meta-analysis found they improved overall survival. "As a result, anthracyclines-based regimens have been long regarded as the standard therapeutic option in the vast majority of early breast cancer patients. However, when individual trials are taken into account, the absolute magnitude of this benefit is not consistent across studies," she added.