Narmeen S Rashid, Nayan Lamba, Ivy Ricca, Marciana Johnson, Paul J Catalano, Shyam K Tanguturi, Rifaquat Rahman, Daphne A Haas-Kogan, Patrick Y Wen, Sarah L Sammons, Nancy U Lin, Ayal A Aizer
Limited data on the timing of brain metastases development and subsequent prognosis by breast cancer subtype exist. We retrospectively evaluated a cohort of 671 patients diagnosed with brain metastases secondary to breast cancer. Patients were categorized by subtype: human epidermal growth factor receptor 2-positive (HER2+), hormone receptor-positive/HER2-negative (HR+/HER2-), and triple negative (TN). We found significant heterogeneity in the timing of brain metastases development and subsequent prognosis by subtype. Patients with HR+/HER2- disease developed brain metastases later in the disease course compared to patients with HER2+ and TN disease. Median overall survival following brain metastases diagnosis was shortest in patients with TN disease; however, among all subtypes, overall survival decreased with an increasing number of systemic therapies prior to the diagnosis of brain metastases. Altogether, these findings may inform differential timing of brain-directed screening imaging in patients with breast cancer.