Navigating Endocrine Sensitivity Assessment in Nonmetastatic Breast Cancer Through Early On-Treatment Ki67 Understanding.

In the landscape of breast cancer management, precise assessment of endocrine sensitivity significantly influences therapeutic strategies. The utilization of Ki67, an immunohistochemical marker of tumor proliferation, in tumor rebiopsy holds paramount importance in unraveling breast cancer's response to endocrine therapy. This narrative review aims to elucidate the pivotal role of Ki67 in endocrine sensitivity assessment. We explore the nuanced process of Ki67 evaluation, its timing, and its implications for clinical outcomes in breast cancer patients. From a clinical perspective to pathological response and risk of recurrence, we navigate the spectrum of Ki67's impact. By delving into these facets, we underscore Ki67's potential to guide personalized treatment strategies, shedding light on the intricate interplay between endocrine therapy and clinical outcomes in breast cancer patients.