Detection of breast cancer metastasis in sentinel lymph nodes using intra-operative real time GeneSearchtrade mark BLN Assay in the operating room: results of the Cardiff study.
Background Intra-operative assessment is not routinely performed in the UK due to poor sensitivity of available methods and overburdened pathology resources. We conducted a prospective clinical feasibility study of the GeneSearchtrade mark Breast Lymph Node (BLN) Assay (Veridex, LLC, Warren, NJ) to confirm its potential usefulness within the UK healthcare system. Methods In the assay 50% of the lymph node was processed to detect the presence of cytokeratin-19 and mammaglobin mRNA. The assay was calibrated to detect metastases >0.2 mm. Assay results were compared to H&E performed on each face of ~2 mm alternating node slabs and 3 additional sections cut at ~150 mum interval from each face of the node slab. Results 124 sentinel lymph nodes were removed from 82 breast cancer patients. The assay correctly identified all 6 patients with sentinel node macrometastases (>2.0 mm), and 2 of 3 patients with sentinel node micrometastases (0.2-2.0 mm). Sentinel lymph nodes in 4 patients were assay positive but histology negative. Two of these four patients had isolated tumor cells seen by histology. The overall concordance with histology was 93.9% (77/82), with sensitivity of 88.9% (8/9, 95% CI 56.5-98%), specificity of 94.6% (69/73, 95% CI 86.7-97.8%), positive predictive value of 66.7% (8/12, 95% CI 39.1-86.2%) and negative predictive value of 98.6% (69/70, 95% CI 92.3-99.7%). The assay was performed in a median time of 32 min (range 26-69 min). Conclusion Intra-operative assessment of sentinel lymph node can be performed rapidly and accurately using the GeneSearchtrade mark BLN Assay.