Early and Locally Advanced Metaplastic Breast Cancer: Presentation and Survival by Receptor Status in Surveillance, Epidemiology, and End Results (SEER) 2010–2014

Background. Metaplastic breast cancer (MBC) is a rare disease subtype characterized by an aggressive clinical course. MBC is commonly triple negative (TN), although hormone receptor (HR) positive and human epidermal growth receptor 2 (HER2) positive cases do occur. Previous studies have reported similar outcomes for MBC with regard to HR status. Less is known about outcomes for HER2 positive MBC.