Breast Lymph Node Assay Research Articles

Comparative Evaluation of an Extensive Histopathologic Examination and a Real-Time Reverse-Transcription-Polymerase Chain Reaction Assay for Mammaglobin and Cytokeratin 19 on Axillary Sentinel Lymph Nodes of Breast Carcinoma Patients

To assess the accuracy of a commercially available real-time reverse-transcription-polymerase chain reaction assay for mammaglobin and cytokeratin 19 mRNAs [GeneSearch Breast Lymph Node (BLN) Assay, Veridex LLC, Warren, NJ] in the detection of axillary sentinel lymph nodes (SLNs) metastases in patients with breast carcinoma. Because of the lack of standardized and widely accepted protocols for a truly accurate histopathologic examination of SLN, the relative merits of alternative assays based on the identification of tumor specific mRNA markers deserve further assessment. : A prospective series of 293 consecutive SLNs from 293 patients was evaluated. The BLN assay results were compared with those of an extensive histopathologic examination of the entire SLNs performed on serial frozen sections cut at 40 to 50 microm intervals. The BLN assay correctly identified 51 of 52 macrometastatic and 5 of 20 micrometastatic SLNs, with a sensitivity of 98.1% to detect metastases larger than 2 mm, 94.7% for metastases larger than 1 mm, and 77.8% for metastases larger than 0.2 mm. The overall concordance with histopathology was 90.8%, with specificity of 95.0%, positive predictive value of 83.6%, and negative predictive value of 92.9%. When the results were evaluated according to the occurrence of additional metastases to non-SLN in patients with histologically positive SLNs, the assay was positive in 33 (91.7%) of the 36 patients with additional metastases and in 22 (66.6%) of the 33 patients without further echelon involvement. The sensitivity of the reverse-transcription -polymerase chain reaction assay is comparable to that of the histopathologic examination of the entire SLN by serial sectioning at 1.5 to 2 mm.

The utility of an investigational real-time RT-PCR assay system for the detection of micrometastases in sentinel lymph nodes of breast cancer confirmed by 0.2 mm histological interval analysis

10560 Background: Comparison between real-time RT-PCR and histological analysis for the detection of lymph node metastasis in breast cancer patients is difficult because of the necessary use of different tissue for the two tests. In order to minimize this challenge this study used histology sections taken every 0.2 mm and all tissue between the sections was analyzed by real-time RT-PCR. Methods: 129 Lymph nodes (LNs) were obtained by Sentinel LN biopsy and/or axillary dissection from 80 breast cancer patients. All LNs were cut in half. One half of each LN was used for the routine intra-operative diagnosis. The other half was used for the 0.2mm histological interval analysis. All 10μm sections cut for histology at 0.2 mm intervals were analyzed using frozen section H&E under a light microscope. All remaining tissue between the sections used for histological analysis was assayed by real-time RT-PCR using the genetic markers mammaglobin and cytokeratin-19 (investigational GeneSearch Breast Lymph Node Assay, Veridex, LLC, Warren, NJ, USA). Cutoffs were pre- set for the real-time RT-PCR to detect only metastasis greater than 0.2 mm. Results: Compared to the histological diagnosis using 0.2 mm interval frozen sections, the real-time RT-PCR results were as follows; sensitivity of 100.0% (34/34), specificity of 93.7% (89/95) and overall accuracy of 95.3% (123/129). Conclusions: These data suggest by utilizing the 0.2 mm histological interval analysis, sampling discrepancies are minimized and a high level of sensitivity and overall accuracy is seen for the real-time RT-PCR assay. Assay specificity calculations may be less than 100% due to interpretation challenges in frozen section histology, especially in the cases of smaller metastases and/or lobular cancer, causing a small percentage of clinically relevant metastasis to be missed. [Table: see text]

An investigational rapid RT-PCR assay for the detection of metastasis in sentinel lymph nodes shows improved performance over frozen section H&E: Analysis by primary tumor characteristics

10561 Background: In order for a RT-PCR test to accurately diagnose the metastatic status of sentinel lymph nodes the test must perform well across all primary tumor types. Methods: A prospective study was conducted at 11 clinical sites to evaluate a real- time RT-PCR assay (investigational GeneSearch™ Breast Lymph Node Assay, Veridex, LLC, Warren, NJ, USA) for the detection of sentinel lymph node metastasis in patients with invasive breast cancer. Detection limits were pre-set to detect only metastases that are clinically relevant (> 0.2 mm). Tumor information such as tumor stage, size, type and other molecular characteristics were collected. RT-PCR assay was then compared against permanent section H&E and IHC for final performance calculations. A total of 416 patients’ results were analyzed for overall assay performance: sensitivity 87.6% and specificity 94.2%. The assay was then evaluated within each primary tumor characteristics category. Results: Overall RT-PCR sensitivity is an improvement (p= 0.039) over that of current intra-operative methods (frozen section H&E), while specificity is similar (p=0.054). For the various tumor sub-types, in a matched dataset, the RT-PCR assay has up to 35.7% (Invasive Lobular) higher sensitivity compared to frozen section H&E. Conclusions: The data suggest that the RT-PCR assay performs well and has higher sensitivity than frozen section H&E regardless of primary tumor characteristics and, therefore, can be used to detect metastasis for all types of invasive breast cancer. [Table: see text] No significant financial relationships to disclose.