Management of Advanced Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer and Brain Metastases: ASCO Guideline Update.

To provide updated evidence- and consensus-based guideline recommendations to practicing oncologists and others on the management of brain metastases for patients with human epidermal growth factor receptor 2 (HER2)-positive advanced breast cancer up to 2021. An Expert Panel conducted a targeted systematic literature review (for both systemic therapy for non-CNS metastases and for CNS metastases of HER2+ guideline updates) that identified 545 articles. Outcomes of interest included overall survival, progression-free survival, and adverse events. Of the 545 publications identified and reviewed, six on systemic therapy were identified to form the evidentiary basis for the systemic therapy for CNS metastases guideline recommendations. Patients with brain metastases should receive appropriate local therapy and systemic therapy, if indicated. Local therapies include surgery, whole-brain radiotherapy, and stereotactic radiosurgery. Memantine and hippocampal avoidance should be added to whole-brain radiotherapy when possible. Treatments depend on factors such as patient prognosis, presence of symptoms, resectability, number and size of metastases, prior therapy, and whether metastases are diffuse. Other options include systemic therapy, best supportive care, enrollment onto a clinical trial, and/or palliative care. There are insufficient data to recommend for or against performing routine magnetic resonance imaging to screen for brain metastases; clinicians should have a low threshold for magnetic resonance imaging of the brain because of the high incidence of brain metastases among patients with HER2-positive advanced breast cancer.Additional information is available at www.asco.org/breast-cancer-guidelines.