More than 280,000 women in the United States will be diagnosed with invasive breast cancer this year. For those with metastatic breast cancer with distant spread, the 5-year survival rate is approximately 28%. Whether advanced disease is discovered at initial diagnosis or in relapsed disease, it is imperative to understand the molecular characteristics of the metastatic tumor.
Dr Susan Domchek, from the University of Pennsylvania, discusses the importance of retesting for estrogen receptor, progesterone receptor, and HER2/ neu on a metastatic tumor focus in order to identify potential discordance between the primary cancer and metastatic disease.
Additionally, Dr Domchek discusses the importance of molecular testing for targetable mutations, including P13K and germline BRCA1/2, for which approved therapies have shown survival benefit.
The list of targetable mutations in breast cancer continues to expand. In the tumor-agnostic studies, pembrolizumab has shown survival benefit in tumors that have mismatch repair deficiency and microsatellite instability, and TRK inhibitors have shown efficacy in tumors positive for NTRK fusions. Numerous clinical trials are available looking at additional molecular-based therapies.
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Susan M. Domchek, MD, Basser Professor, Department of Oncology; Executive Director, Basser Center for BRCA, Abramson Cancer Center, University of Pennsylvania, Philadelphia.
Susan M. Domchek, MD, has disclosed the following relevant financial relationships: Received income in an amount equal to or greater than $250 from: AstraZeneca; Clovis; Bristol Myers Squibb.