HER2-positive Breast Cancer With Brain Metastasis (GCC 1345)

Metastatic breast cancer is a leading cause of death for women. HER2(human epidermal growth factor receptor type 2)-positive disease represents a more aggressive type of breast cancer which often afflicts younger patients. As many as one-third of patients with HER2-positive breast cancer develop brain metastasis\[1\]. The development of brain metastasis in this young female population is particularly devastating as they are often highly functional and may have young children. Improvement in quality of life by preventing neurocognitive decline from disease progression and/or treatment related side effects is paramount. Patients with 1-10 brain metastasis from HER2+ breast cancer, after informed consent, will be treated with: Radiosurgery: Gamma-knife, Cyberknife, or linac-based SRS is followed by anti-HER2 based systemic therapy, with the treatment selection of approved agents at the physician's discretion. Possible anti-HER2 agents include trastuzumab, pertuzumab, trastuzumab-emtansine, or lapatinib. Anti-HER2 therapy will be delivered in combination with appropriate cytotoxic therapy as per FDA indications. Anti-HER2 based systemic therapy will continue until progression, patient discontinuation, unacceptable toxicity or if, in the view of the physician it is no longer indicated. MRI and neurocognitive testing will be done prior to SRS and repeated every 3 months during the first 6 months from enrollment. Patients can only be enrolled after all eligibility criteria are met. The date of registration/enrollment is considered to be the day the Eligibility Checklist is signed by the verifying physician. Once a patient is enrolled, a unique case number will be assigned to the patient.