Predictive Value of Magee Equation 3 for Tumor and Axillary Response to Neoadjuvant Chemotherapy in HR-Positive, HER2-Negative Breast Cancer.

This article focuses on evaluating the predictive value of Magee Equation 3 (ME3), a score derived from routine immunohistochemical markers, for assessing both primary tumor and axillary response to neoadjuvant chemotherapy (NACT) in hormone receptor-positive (HR+), HER2-negative breast cancer. In a retrospective study of 116 patients, higher ME3 scores (>31) were significantly associated with increased rates of pathological complete response (pCR) in both the primary tumor and axillary lymph nodes, while no pCR was observed in patients with low ME3 scores (<18). Receiver operating characteristic analysis identified ME3 cut-offs that effectively predicted tumor and axillary responses, suggesting ME3 as a practical, cost-effective alternative to genomic assays for guiding treatment and surgical planning, especially in settings with limited access to genomic testing. The study highlights ME3's potential role in individualized therapy decisions but notes the need for prospective multicenter validation before widespread clinical adoption.