Heather McArthur, MD, and Debu Tripathy, MD, lead a discussion on risk stratification and optimizing treatment for HER2+ early breast cancer (eBC), followed by a review of standard-of-care systemic therapy regimens in the preoperative/neoadjuvant setting.
Sara Hurvitz, MD: Hello, and welcome to this OncLive® Peer Exchange® titled “HER2+ Breast Cancer: Recent Data Updates and Key Advances.” I’m Sara Hurvitz, a medical oncologist and the director of the breast oncology program at UCLA [University of California, Los Angeles]. I’m joined by a panel of experts in the field of HER2 [human epidermal growth factor receptor 2]–positive breast cancer. I’d like to welcome my esteemed fellow panelists to introduce themselves. Virginia?
Virginia G. Kaklamani, MD, DSc: I’m Virginia Kaklamani. I’m a professor of medicine at UT [University of Texas] Health San Antonio, and I head our breast program.
Sara Hurvitz, MD: Welcome. Heather?
Heather McArthur, MD: I’m Heather MacArthur. I’m the clinical director of breast cancer at UT Southwestern [Medical Center] in Dallas, Texas.
Sara Hurvitz, MD: Welcome. Melinda?
Melinda Telli, MD: I’mMelinda Telli from Stanford University [in Palo Alto, California]. I serve as the director of the breast cancer program.
Sara Hurvitz, MD: Welcome. And Debu?
Debu Tripathy, MD: I’m Dr Debu Tripathy at the University of Texas MD Anderson Cancer Center [in Houston]. I’m a professor and the chair of the department of breast medical oncology.
Sara Hurvitz, MD: Welcome, everyone. Thank you for joining me. This is going to be great. We’re going to discuss recent data updates on treatment and management of HER2+ breast cancer, including data presented at the ASCO [American Society of Clinical Oncology Annual Meeting] 2023, and how these data may impact practice. Let’s get started on our first topic, which is the preoperative or neoadjuvant treatment landscape for HER2+ early breast cancer. I’d like to turn to Heather about how we typically treat patients in this setting and the typical prognosis associated with this type of disease.
Heather McArthur, MD: Fortunately, because of successful drug development, we’ve seen unprecedented improvements in overall survival and cure rates for patients with HER2+ early stage breast cancer. Historically, we’ve relied on conventional clinical and pathological features to predict response and outcomes. We’re increasingly seeing genomics applied, as we have in HER2-negative disease, with assays like HER2DX incorporating clinical features and gene expression assays to prognosticate and predict responses. It’s an incredibly exciting time. The focus is about treatment optimization for our patients: de-escalating treatment for those at a lower risk to obtain those excellent cure rates, but escalating and offering more promising therapies for those at higher risk.
Sara Hurvitz, MD: It’s an incredibly exciting time. Understanding how to tailor therapy to risk is becoming the tricky part of our jobs. Debu, take us through some of the standard-of-care regimens for preoperative neoadjuvant therapy for HER2+ breast cancer. Do all patients require preoperative therapy? Do some get to go directly to surgery? How do you manage this?
Debu Tripathy, MD: Preoperative therapy is important in that it can reduce tumor size and make possible more breast-conserving surgery and less lymph nodal surgery. It also predicts which patients may be at a higher risk if they have residual disease, and that influences adjuvant treatment choices. On the other hand, for smaller tumors, we’re using de-escalated therapies such as paclitaxel and trastuzumab alone. I tend to use neoadjuvant therapy in patients who have larger tumors over 2 cm or any node positivity. That corresponds with the low-risk group, those that are 2 or 3 cm but node negative. There we can use the APT regimen, which is weekly [adjuvant] paclitaxel and trastuzumab for a full year overlapping with paclitaxel. Then that leaves for neoadjuvant therapy: docetaxel, trastuzumab, pertuzumab, and sometimes carboplatin.
Sara Hurvitz, MD: Thank you. Making a decision about whom to take to surgery first is very nuanced. If there’s nodal involvement, a tumor size of 2 or 1.5 cm, would you use neoadjuvant therapy? Or [would you] go straight to surgery?
Debu Tripathy, MD: If you’re going to use de-escalated therapy, I’ll typically do that for 2 cm or lower node negative. That’s based on clinical staging because, at that point, they would go to surgery to confirm that they’re at stage I and that they don’t have occult positive nodes. Then I’d use a different adjuvant regimen. If I confirm that they’re pathological stage I, or up to 3 cm in size, then I’d use the APT [adjuvant paclitaxel and trastuzumab] de-escalated regimen. Whereas if they end up being upstaged, I’d use 1 of the neoadjuvant regimens, which includes pertuzumab and trastuzumab.
Transcript edited for clarity.