BACKGROUNDSentinel 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.

METHODSThe 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.

RESULTSA 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).

CONCLUSIONThe 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.