According to a recent article published in The Lancet, genetic profiling using microarray analysis may predict a breast cancer patient’s response to neoadjuvant Taxotere® (docetaxel).
Breast cancer claims the lives of approximately 40,000 women and is diagnosed in approximately 200,000 women annually in the United States alone. Chemotherapy remains a mainstay in therapeutic regimens offered to patients with breast cancer, particularly those who have cancer that has spread from its site of origin. There are several chemotherapy agents that have demonstrated activity in the treatment of breast cancer and research is continuous in an attempt to determine optimal chemotherapy agents and regimens. However, different patients tend to respond differently to the same therapeutic regimen, implying differences in genetic profiles. Cancers contain different genetic mutations and researchers are now realizing that different genetic variables affect how a cancer will respond to various therapies. As research involving genetics and associated responses to treatment matures, standard practice will undoubtedly become more individualized, enabling physicians to provide specific treatment regimens matched with a patient’s genetic mutation(s) to ensure optimal outcomes.
Taxotere® is one of the most active agents in the treatment of breast cancer. However, some women are inherently resistant to Taxotere® and do not respond to treatment involving this agent. Researchers from the Baylor College of Medicine and the Methodist Hospital in Houston, Texas recently conducted a clinical study in an attempt to distinguish genetic mutations that make patients either susceptible or resistant to the anti-cancer effects of Taxotere®. This study involved 24 patients with operable breast cancer. Biopsies (samples of cancer cells) were obtained from each patient prior to therapy with Taxotere®. The cancer cells were processed in the laboratory to determine differences in the levels of expressions of genes, and these differences were compared to a patient’s response to treatment. Overall, the researchers identified 92 genes that were indicative of response or resistance to treatment with Taxotere®. Accuracy of these 92 genes in determining a response or resistance to Taxotere® was 92% and 83%, respectively.
The researchers concluded that genetic profiling may provide great accuracy in determining which patients would benefit from a specific treatment and which patients would be receiving unnecessary treatment with a specific agent. Specifically, the 92-gene predictor model discovered in this trial may be used to determine a patient’s response to Taxotere®, providing a platform from which to begin individualized treatments. However, the authors state that these results are preliminary and need confirmation. Researchers affiliated with the National Cancer Institute have initiated a large clinical trial to further evaluate molecular profiling in patients with breast cancer utilizing several different chemotherapy agents. Patients with breast cancer may wish to speak with their physician about the risks and benefits of participating in a clinical trial further evaluating genetic profiling or novel therapeutic approaches. Sources of information regarding ongoing clinical trials include the National Cancer Institute (cancer.gov).
Reference: Chang J, Wooten E, Tsimelzon A, et al. Gene expression profiling for the prediction of therapeutic response to docetaxel in patients with breast cancer.
The Lancet. 2003;362: 362-369.