HER2-Positive Breast Cancers Respond Better to Anthracyclines

HER2-Positive Breast Cancers Respond Better to Anthracyclines

According to an article recently published in the New England Journal of Medicine, premenopausal women with HER2-positive breast cancers had improved outcomes with a chemotherapy regimen containing an anthracycline. Conversely, those women with HER2-negative breast cancers did not achieve benefit from the addition of an anthracycline to their treatment regimen.

A significant portion of women diagnosed with breast cancer have what is called HER2-positive breast cancer. Patients with HER2-positive breast cancer have cancer that has one or more mutations (genetic alterations) within the human epidermal growth factor receptor-2 (HER2) pathway.

Mutations within the HER2 result in overproduction of the HER2 receptor, which is found on the outside of cancer cells. Patients who have an excess amount of these receptors are referred to as HER2-positive.

All women with breast cancer should undergo testing to determine if their cancer is HER2-positive.

Anthracyclines are chemotherapy agents that are effective in the treatment of breast cancer; Ellence® (epirubicin) and Adriamycin® (doxorubicin) are both anthracyclines. Though effective, anthracyclines tend to be difficult to tolerate and may cause long-term damage to the heart.

Researchers affiliated with the National Cancer Institute of Canada Clinical Trials Group recently evaluated data to determine if outcomes are different between women with HER2-positive and HER2-negative breast cancers when treated with different chemotherapy regimens.

The data included 710 premenopausal women who had been diagnosed with node-positive (cancer spread to lymph nodes under the arm), HER2-positive or HER2-negative breast cancer. Some women had been treated with the chemotherapy regimen CEF (cyclophosphamide, epirubicin, and fluorouracil), and some had been treated with CMF (cyclophosphamide, methotrexate, and fluorouracil). The CMF regimen tends to have fewer side effects and tends to be much better tolerated that CEF.

  • Patients with HER2-positive breast cancers had improved outcomes with CEF compared to CMF.
  • Patients with HER2-negative breast cancer had comparable outcomes with the two chemotherapy regimens.
  • Among patients with HER2-positive breast cancer, survival without a recurrence of cancer was improved by 48%, and overall survival was improved by 35% among women treated with CEF compared to those treated with CMF.

The researchers concluded that premenopausal women with HER2-positive, node-negative breast cancer have improved outcomes when treated with CEF compared to CMF. Conversely, women with HER2-negative cancer do not have improved outcomes with CEF compared to CMF. Future trials using the addition of Herceptin® (bevacizumab), an agent targeted against HER2-positive breast cancer, with either of these regimens may be warranted.

Premenopausal women with node-negative breast cancer may wish to speak with their physician regarding their individual risks and benefits of all treatment choices.

Reference: Pritchard K, Shepherd L, O’Malley F, et al. HER2 and Responsiveness of Breast Cancer to Adjuvant Chemotherapy. New England

Journal of Medicine. 2006; 354:2103-2111

Related News: Repeat Use of Anthracyclines May Not Be Warranted in Breast Cancer (5/17/2006)

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