Eighteen months clinical experience with the GeneSearch breast lymph node assay.

Background: The accuracy of a molecular reverse transcriptase-polymerase chain reaction (RT-PCR)-based assay for metastases detection in axillary sentinel lymph nodes (SLNs) has recently been validated in our institution and adopted as an intraoperative test for breast cancer patient management.
Methods: Molecular assay performance was compared to standard postoperative histology in 253 consecutive patients with clinically node-negative T1 early breast cancer (<2 cm).
Results: The molecular assay correctly identified 26/27 macrometastases and 11/15 micrometastases. Overall concordance with histopathology was 93%, with 87% sensitivity, 94% specificity, and 75% positive and 97% negative predictive values. The molecular assay was positive in 13/14 patients with SLNs and nonsentinel lymph node (axillary lymph node [ALN])-positive histology. Notably, 2/12 patients with assay-positive/histology-negative SLNs exhibited ALN positivity.
Conclusions: This molecular assay can raise the standard of care for patient management as its accuracy is similar to that of standard postoperative histology with the advantage of being standardized, objective, and fast enough for intraoperative use.