HER2/neu Positive Breast Cancer Associated with Clinical Responsiveness to Adjuvant Chemotherapy
Women with HER2/neu positive breast cancer may benefit from anthracycline-containing chemotherapy
By Anna Shaffer, LBBC Staff
Kathleen Pritchard, et. al., HER2 and Responsiveness of Breast Cancer to Adjuvant Chemotherapy. The New England Journal of Medicine. 18 May 2006.
Women with HER2/neu positive breast cancer may respond better to an anthracycline-containing chemotherapy regimen than to one that doesn’t contain an anthracycline, says a recent study.
Kathleen I. Pritchard, MD, of the University of Toronto in Ontario, reported in the May 18, 2006, issue of
The New England Journal of Medicine that although HER2/neu positive breast cancer was associated with a poor prognosis regardless of the type of treatment, women with HER2/neu positive tumors may benefit more from regimens that use a combination of cyclophosphamide, epirubicin and fluorouracil (CEF) while those whose tumors are HER2/neu negative could be treated with a less toxic regimen of cyclophosphamide, methotrexate and fluorouracil (CMF). Study results suggest tumors that are HER2/neu negative do not differ significantly in their response to chemotherapy with CEF or with CMF.
What Makes This Study Important?
On healthy cells, the HER2 gene helps control the growth of cells. But in one-third to one-fifth of breast cancers, the HER2 gene becomes “amplified” or “overexpressed,” producing extra copies of itself or too many proteins. HER2/neu positive breast cancers tend to grow and spread faster and are more likely to invade neighboring tissue, spread to distant organs and stimulate blood vessel growth within a tumor that encourages it to grow.
Results of this study suggest women whose tumors are HER2/neu negative can be treated with the less toxic regimen of CMF, whereas those with HER2/neu positive tumors should receive dose-intensive anthracycline-containing regimens such as CEF. With the advent of trastuzumab (brand name: Herceptin), a medicine that works by targeted the HER2/neu gene, anthracyclines may not be required. However, the results of this study represent a step forward in anthracycline tailoring.
Goals/Design of Study
Previous studies have shown that CEF used to treat breast cancer led to increased overall survival compared with a regimen of CMF. However, CEF has more side effects and is more expensive.
Dr. Pritchard and her team theorized that CEF preferentially benefited tumors that amplified HER2. To test their theory, they studied the HER2/neu status of 639 tumor specimens from 710 premenopausal women with node-positive breast cancer who had participated in the National Cancer Institute of Canada Clinical Trials Group Mammary.5 (MA.5) study, a randomized, controlled trial. All women had received either CEF or CMF as adjuvant chemotherapy.
Study Results
Researchers found that women with HER2/neu positive breast cancer had decreased relapse-free and overall survival regardless of the type of treatment compared to those whose tumors were HER2/neu negative. However, women with HER2/neu positive breast cancer responded better to CEF than to CMF, while women with HER2/neu negative breast cancer did not differ significantly in their response to chemotherapy with CEF or with CMF.
What These Results Mean for Me
Results of this study indicate that amplification of HER2 in breast cancer cells is associated with responsiveness to anthracycline-containing chemotherapy. If you have been diagnosed with HER2/neu positive breast cancer, the authors of this study assert that receiving dose-intensive anthracycline-containing regimens such as CEF may benefit you. However, if you have been diagnosed with HER2/neu negative breast cancer, you could be treated with the less toxic regimen of CMF.
If you have been diagnosed with HER2/neu positive breast cancer, you may want to discuss CEF and other anthracycline-containing treatment options with your healthcare provider.
Read the abstract from the HER2 study.
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