Background: Sentinel lymph node (SLN) biopsy has become a common procedure for early breast cancer patients. The GeneSearch(TM) Breast Lymph Node (BLN) Assay is a real-time RT-PCR assay for the detecting nodal metastases larger than 0.2 mm. China Breast Cancer Clinical Study Group (CBCSG)-001a is a prospective multi-center clinical trial that was conducted to validate the GeneSearch(TM) BLN Assay in China.
Methods: The SLNs from 90 consecutive patients were identified and dissected, and then sectioned along the short axis into multiple blocks. Intra-operatively, the odd blocks were tested by BLN assay and the even ones were used for frozen section, while all the blocks were evaluated by touch imprint cytology. Post-operatively, the remaining tissues were assessed by histological evaluation.
Results: A total of 189 SLNs was tested by BLN assay. The sensitivity, specificity, positive predictive value, and negative predictive value were 88.9%, 97.4%, 88.9% and 97.4%, respectively, for BLN assay, 75.0%, 100%, 100% and 94.4%, respectively, for frozen section, and 63.9%, 100%, 100% and 92.2%, respectively, for touch imprint cytology. The sensitivity of BLN assay was higher than that of touch imprint cytology (P = 0.01) and frozen section (P = 0.13). When assessing the nodes with micro-metastases, BLN assay had a significant higher sensitivity than frozen section (P = 0.023) and touch imprint cytology (P = 0.005).
Conclusion: The GeneSearch(TM) BLN Assay is an accurate and rapid intra-operative assay for breast SLNs and it is suitable for application in general medical practice.