According to a recent article published in the journal Clinical Cancer Research, gene expression profiling may help define which subtypes of breast cancer will respond to specific chemotherapy agents that are used prior to surgery. As gene-expression profiling emerges into the clinical setting of oncology, these results, if verified with further studies, may help guide individualized treatment for patients with this disease.
Breast cancer is the most commonly diagnosed cancer in women in the United States. Although cure rates have improved dramatically over the past few decades, a significant portion of women with breast cancer still experience a recurrence and die from their disease. Gene-expression profiling is a laboratory test that determines activity of specific genes or patterns of genes in a patient’s cancerous tissues. Researchers are finding that gene-expression profiling is providing vital information into why some patients respond to certain therapies and some do not.
Some patients with early breast cancer are treated with chemotherapy prior to surgery (neoadjuvant therapy). Neoadjuvant therapy is intended to shrink the cancer to allow more complete surgical removal of the cancer. In addition, systemic (full body) treatment can begin immediately, versus waiting for healing after surgery, so that cancer cells that may have spread to other parts of the body are killed prior to further spread.
A recent multi-institutional study was conducted to evaluate the role of gene-expression profiling in determining which patients with early breast cancer will achieve anti-cancer responses to neoadjuvant chemotherapy. The study included cancerous cells from 82 breast cancers. Gene-expression profiling was performed prior to treatment. Neoadjuvant chemotherapy consisted of the commonly used chemotherapy agents Taxol® (paclitaxel), Fluoroplex® (5-fluorouracil), Adriamycin® (doxorubicin), and Cytoxan® (cyclophosphamide). Patients identified as having the subgroups of breast cancers referred to as “basal-like” or “erbB2+” had 45% complete disappearance of cancer (complete response or CR), compared to only 6% in breast cancers classified as “luminal”. No breast cancers classified as “normal-like” demonstrated a CR.
The researchers concluded that genetic profiling may help determine which patients with early breast cancer can achieve acceptable responses to neoadjuvant chemotherapy with Taxol®/5-fluorouracil/ doxorubicin/cycophosphamide. Although longer follow-up is necessary to determine if outcomes are affected by these results, it appears that these results add to a growing body of evidence indicating that genetic profiling may someday play a large part in individualizing treatment options for all patients. The ultimate hope of this method is to improve cure rates. Patients with breast cancer may wish to speak with their physician regarding their individual risks and benefits of participating in a clinical trial further evaluating genetic profiling or other novel approaches to treatment advancements. Two sources of information regarding ongoing clinical trials include the National Cancer Institute (www.cancer.gov) and www.cancerconsultants.com.
Reference: Rouzier R, Perou C, Fraser W, et al. Breast Cancer Molecular Subtypes Respond Differently to Preoperative Chemotherapy. Clinical Cancer Research. 2005; 11, 5678-5685.
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