Objective: To evaluate the value of GeneSearch(TM) BLN assay as an intraoperative diagnostic method of sentinel lymph node metastases in breast cancer patients.
Methods: Ninety consecutive patients were involved in this study. SLNs were intraoperatively identified and dissected, and then sectioned vertically to the long axis into multiple blocks. The odd blocks were tested by BLN assay and even ones prepared for frozen sectioning (FS), while all blocks were evaluated by touch imprint cytology (TIC). Post-operatively, residual tissues of the even blocks were assessed by histopathologic examination (4 - 6 µm thick serial sectioning permanent H&E slides were performed every 150 µm and one block made 6 slides).
Results: BLN assay could be performed within less than 35 min after learning curve of 10 cases. A correlation was found between cycle time values of mammaglobin or cytokeratin-19 and size of metastases, with Spearman correlation coefficients of 0.67 and 0.71, respectively. The accuracy, sensitivity, specificity, positive predict value (PPV) and negative predict value (NPV) of the assay were 95.6%, 93.3%, 96.7%, 93.3% and 96.7%, While FS had the sensitivity, specificity, PPV, NPV of 76.7%, 100%, 100%, 89.6%, and TIC of 73.3%, 100%, 100%, 88.2%, respectively. The sensitivity of the assay was higher than that of FS (P = 0.07), and was significantly higher than that of FS (P = 0.04). When assessing patients with micro-metastases, the assay had a sensitivity of 85.7%, which was significantly higher than that of FS and TIC (P = 0.03).
Conclusion: GeneSearch(TM) BLN Assay can replace FS and TIC for the intraoperative assessment of SLN.