Intraoperative Sentinel Lymph Node Analysis Research Articles

Validation of markers for the intraoperative detection of metastasis in breast sentinel lymph nodes

9547 Background: The presence of axillary lymph node (ALN) metastasis is the most important prognostic factor for breast cancer patients. Sentinel lymph node (SLN) status is highly predictive of overall ALN involvement. SLN-positive patients have historically undergone ALN dissection in a second surgery. Intraoperative SLN analysis methods have been implemented to reduce the cost and complications of second surgeries, but these methods suffer from poor and variable sensitivity and a lack of standardization. We are investigating the feasibility of RT-PCR as the basis for improving the intraoperative diagnosis of clinically relevant SLN metastasis. Methods: Eight molecular markers, including mammaglobin, were identified from a genome-wide gene expression analysis of breast and other tissues. Alternate serial sections of SLN from 254 breast cancer patients were analyzed by permanent section H&E or quick frozen for RNA extraction. Blinded SLN cDNAs were analyzed by quantitative RT-PCR. PCR signal was compared to H&E results on a patient basis. Using multivariate receiver operating curves (ROCs), PCR cut-offs were selected that optimally correlated with H&E results. Results: A two-gene assay (mammaglobin and VBM1) detected clinically actionable metastasis (> 0.2 mm) with 90% sensitivity and 94% specificity. The performance of this marker combination was validated by leave half out cross-validation. Addition of a third gene had minimal impact on overall performance. Conclusions: This is the first comprehensive study demonstrating the utility of RT-PCR as the basis of an intraoperative assay for detecting clinically actionable breast metastasis. Mammaglobin / VBM1 expression closely correlates with standard H&E detection of SLN metastasis, demonstrating that molecular analysis has the potential to significantly reduce second surgeries for patients undergoing SLN biopsies. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Veridex, LLC, a Johnson & Johnson Co. Veridex, LLC, a Johnson & Johnson Co. Veridex, LLC, a Johnson & Johnson Co. Veridex, LLC

Validation of markers for the intraoperative detection of metastasis in breast sentinel lymph nodes

9547 Background: The presence of axillary lymph node (ALN) metastasis is the most important prognostic factor for breast cancer patients. Sentinel lymph node (SLN) status is highly predictive of overall ALN involvement. SLN-positive patients have historically undergone ALN dissection in a second surgery. Intraoperative SLN analysis methods have been implemented to reduce the cost and complications of second surgeries, but these methods suffer from poor and variable sensitivity and a lack of standardization. We are investigating the feasibility of RT-PCR as the basis for improving the intraoperative diagnosis of clinically relevant SLN metastasis. Methods: Eight molecular markers, including mammaglobin, were identified from a genome-wide gene expression analysis of breast and other tissues. Alternate serial sections of SLN from 254 breast cancer patients were analyzed by permanent section H&E or quick frozen for RNA extraction. Blinded SLN cDNAs were analyzed by quantitative RT-PCR. PCR signal was compared to H&E results on a patient basis. Using multivariate receiver operating curves (ROCs), PCR cut-offs were selected that optimally correlated with H&E results. Results: A two-gene assay (mammaglobin and VBM1) detected clinically actionable metastasis (> 0.2 mm) with 90% sensitivity and 94% specificity. The performance of this marker combination was validated by leave half out cross-validation. Addition of a third gene had minimal impact on overall performance. Conclusions: This is the first comprehensive study demonstrating the utility of RT-PCR as the basis of an intraoperative assay for detecting clinically actionable breast metastasis. Mammaglobin / VBM1 expression closely correlates with standard H&E detection of SLN metastasis, demonstrating that molecular analysis has the potential to significantly reduce second surgeries for patients undergoing SLN biopsies. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Veridex, LLC, a Johnson & Johnson Co. Veridex, LLC, a Johnson & Johnson Co. Veridex, LLC, a Johnson & Johnson Co. Veridex, LLC