The pH Levels of Sentinel Lymph Nodes and the Probability of Cancer Involvement in Breast Cancer Patients: a Cross-Sectional Study

Background: Cancer cells in lymph nodes can undergo metabolic changes, producing acidic byproducts. Our previous experimental results demonstrated significant pH differences between involved and free lymph nodes (LNs), potentially attributed to the release of these acidic byproducts. However, the accuracy of frozen sections is influenced by pathologists' expertise and limited response time. To address these limitations, we developed a simple pH sensing method. Methods: In this paper, we conduct a cross-sectional study on non-neoadjuvant breast cancer patients (n= 34) from Shohada Tjarish Hospital and Azar Surgical Clinic to check the agreement between the pH value of sentinel lymph nodes (SLNs) and their pathologic score. To assess the pH assay's validity in detecting metastasized cancer cells in lymph nodes, the sensitivity, specificity, and accuracy of the sensor were calculated using Permanent pathology of LNs as the reference standard. Results: Results showed that cancer SLNs had pH , while free LNs had pH > 8 (p-value <0.001). The sensitivity and specificity of the data were 89% (95% CI (0.73-1.05)) and 82% (95% CI (0.64-1.00)), respectively. Conclusion: Hence, in the absence of a frozen section, such a simple measurement may assist the surgeon in deciding whether to dissect a further number of LNs or not.