To Rebiopsy or Not? Current Evidence and Ongoing Controversies in Metastatic Breast Cancer Care

Abstract

Rebiopsy in metastatic breast cancer (MBC) is increasingly recognized as an important step in optimizing treatment decisions. This review summarizes current evidence, biological rationale, and practical considerations regarding rebiopsy in MBC. Receptor discordance between primary and metastatic lesions, reported in approximately 10–40% for estrogen receptor (ER), 20–30% for progesterone receptor (PR), and 5–15% for human epidermal growth factor receptor 2 (HER2), may result in clinically meaningful changes in systemic therapy. Although international guidelines recommend rebiopsy at recurrence or metastatic presentation, its implementation remains limited by procedural risks, sampling bias, and logistical constraints. Rebiopsy provides valuable insights into tumor evolution and supports personalized treatment strategies; however, its use should be individualized, balancing potential benefits and risks within a multidisciplinary framework.