One-step nucleic acid amplification assay for intraoperative prediction of non-sentinel lymph node metastasis in breast cancer patients with sentinel lymph node metastasis.

The aim of the present study was to construct the intra-operative prediction model of non-sentinel lymph node (non-SLN) metastasis in breast cancer patients with SLN metastasis using one-step nucleic acid amplification (OSNA). Of 833 breast cancer patients (T1-T2, N0) who underwent SLN biopsy and had their SLNs examined intra-operatively with the OSNA assay, 161 with SLN metastasis and treated with completion axillary lymph node dissection (cALND) were randomly divided into a training (n = 81) and a validation (n = 80) cohort. Non-SLN metastasis of the training cohort was associated with the number of positive SLNs (P = 0.001), CK19 mRNA copy number (P = 0.001), and clinical tumor size (P = 0.055). These parameters were used to construct the intra-operative prediction model of non-SLN metastasis. Its diagnostic accuracy (AUC of ROC curve) was 0.809 and 0.704 for the training and validation cohorts, respectively. The intra-operative prediction model using OSNA may have a diagnostic accuracy of non-SLN metastasis comparable to that of the conventional, post-operative prediction model, indicating that it might help decide the indication for cALND.