HER2-Targeted Therapies With SRS for Breast Cancer Metastatic to the Brain

By: Lauren Harrison, MS
Posted: Wednesday, February 23, 2022

The use of HER2-directed therapies in combination with stereotactic radiosurgery (SRS) in patients with HER2-positive breast cancer and brain metastases led to favorable survival outcomes, in a small patient sample. The results were presented by John W. Shumway, MD, of the University of North Carolina School of Medicine, Chapel Hill, at the 2021 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract 3220) and published in the journal Neuro-Oncology. They also noted that the sequence of systemic therapy and radiosurgery did not appear to impact survival outcomes.

Data were generated from a single-institution retrospective review of patients with biopsy-proven breast cancer that had metastasized to the brain between 2009 and 2020. There were 82 patients treated with SRS, and 33 of them had HER2-positive disease. There were nine patients treated with systemic therapy before SRS; systemic therapies consisted of various combinations of ado-trastuzumab emtansine (T-DM1), trastuzumab, pertuzumab, lapatinib, and chemotherapy. There was a median of 18.6 months between the start of systemic therapy and SRS. However, seven patients received radiosurgery first, followed by systemic therapy (multiagent regimens with T-DM1 or lapatinib). A total of 17 patients received concurrent radiosurgery and systemic therapy (various combinations of T-DM1, chemotherapy, lapatinib, trastuzumab, pertuzumab, and hormone therapy).

The median follow-up for the study cohort was 21.1 months, and the median overall survival was 24.8 months. There was no statistically significant difference in overall survival when patients were grouped by the order they received therapy (ie, systemic therapy first, concurrent radiotherapy and systemic therapy, or radiotherapy first).

Four patients developed symptomatic radionecrosis. Three of them were given concurrent radiotherapy and T-DM1, suggesting a possible increased risk of radionecrosis when these two treatments are used together.

Disclosure: For Dr. Shumway’s disclosures, visit plan.core-apps.com.

Neuro-Oncology

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