Albumin-To-Alkaline Phosphatase Ratio as a New Early Predictive Marker of Axillary Response in Breast Cancer Patients Undergoing Neoadjuvant Chemotherapy: A Pilot Study

Background and Objectives: The Albumin-to-Alkaline Phosphatase ratio (AAPR) is an easily applicable and cost-effective marker investigated as an outcome predictor in solid cancers. Preliminary evidence in breast cancer suggests that a low AAPR correlates with a poor response to neoadjuvant chemotherapy (NAC) in primary tumors. However, data regarding the axillary response are lacking. This study aims to evaluate whether the AAPR can predict the axillary response in initially nodal-positive (cN+) breast cancer patients undergoing NAC. Materials and Methods: Clinical and biochemical variables of cN+ breast cancer patients undergoing NAC were collected. Pre-NAC albumin and alkaline phosphatase serum values were utilized in the AAPR calculation. Fisher’s exact test was performed to identify differences between the two groups of patients (high and low AAPR according to the cut-off reported in the literature). The primary outcome was the nodal pathologic complete response (pCR) rate in the two groups of patients. Results: Nodal pCR was achieved in 20/45 (44.4%) patients. A total of 36/45 (80%) patients had an AAPR > 0.583. Among patient and tumor characteristics, the only statistically significant difference between the two groups was the axillary pCR between the low and high AAPR groups (p-value = 0.03, OR = 0.129, 95% CI = 0.00–0.835). Conclusions: This pilot study suggests that the pre-treatment AAPR might be an early predictor of axillary response in cN+ breast cancer patients undergoing NAC. This result justifies further investigation in larger prospective trials to validate this finding.