[Evaluation of intraoperative molecular assay in sentinel lymph node biopsy from breast cancer patients].

Objective: to evaluate the application of GeneSearch(TM) breast lymph node assay in intraoperative detection of metastases in sentinel lymph node (SLN) from breast cancer patients.

Methods: a total of 225 SLN from 88 patients was prospectively studied. Each SLN was cut into 2 mm slabs which were examined by intraoperative imprint cytology (IIC) first, followed by GeneSearch assay and post-operative serial sectioning. GeneSearch used real-time fluorescence quantitative RT-PCR technology to detect the expression of CK19 and mammaglobin in SLN. The results of GeneSearch assay were correlated with those of IIC and post-operative serial sectioning.

Results: amongst the 88 cases studied, 225 SLNs were found, and obvious metastatic carcinoma cells were identified in 27 SLNs and micrometastasis in 9 SLNs. One hundred and eight-nine SLNs were considered as "negative" (with "isolated tumor cells" present in 5 SLNs). The turn-around time of intraoperative GeneSearch assay ranged from 35 to 45 minutes (mean = 40 minutes). The concordance rate between GeneSearch assay and post-operative serial sectioning was 95.6% (215/225), with a sensitivity of 86.1% (31/36), compared with 94.7% (213/225) and 72.2% (26/36) respectively for IIC. The size of metastatic foci correlated with the Ct value of CK19 and mammaglobin (P < 0.01).

Conclusions: GeneSearch assay for intraoperative detection of metastase in SLN has a satisfactory performance and demonstrates a relatively higher sensitivity than IIC. The potential clinical application still requires further evaluation of larger number of cases.