Objective: To determine whether the total tumor load (TTL) as indicated through the one-step nucleic acid amplification
(OSNA) assay can be a predictive factor of non-sentinel lymph node (SLN) metastasis in early breast cancer patients.
Material and Method: The records of 102 patients with cT1-3N0 breast cancer who had an intraoperative SLN evaluation
performed through an OSNA assay at Songklanagarind Hospital between 1 January 2015 and 30 May 2016 were examined.
Results: Univariate analysis found TTL, tumor size, presence of lymphovascular invasion, and macrometastasis were
significant predictive factors of non-SLN metastasis. In the multivariate analysis, TTL was the only predictive factor with
statistical significance (OR 1.1, 95% CI=1.0, 1.2). The area under the receiver operating characteristics (ROC) curve of
TTL was 0.9 (95% CI=0.8, 0.9).
Conclusion: TTL is a significant predictive factor of non-SLN metastasis in early breast cancer patients.