Blue-dye Assisted Axillary Node Sampling And Intraoperative Detection Of Micrometastasis In Women With Breast Cancer

The status of axillary lymph nodes remains the single most important prognostic factor and the most important factor when deciding on surgical decision-making, adjuvant chemoradiation therapy and for predicting outcome. Sentinel lymph node biopsy (SLNB) and axillary node sampling (ANS) have been used to predict axillary lymph node metastasis in western countries during the past two decades. However, the optimum techniques for lymphatic mapping as well as the pathological examination of sentinel lymph nodes (SLNs) are still under debate.The present study, divided into two sections, was undertaken to develop a reasonable workload in lymphatic mapping and diagnosis of lymph nodes resected, in which the first section were to establish which route of injection, peritumorally or subareolarly, could provides the greatest frequency of success for localization of a SLN, and whether the addition of axillary node sampling could improved the overall accuracy; the second section was to determine the best technique for rapid lymph node assessment.Section One: Sixty-four patients with stage I, II primary invasive breast cancer underwent randomization to one of two blue-dye alone injection routes, with 33 (51.6 %) SA, and 31 (48.4%) PT. After anesthesia, 4-6 ml of 1% methylene blue dye was injected into four locations subareolarly and peritumorally. A transverse skin incision was made in the breast 5 min after injection, then blue lymphatic channels were carefully pursued until they entered the lymph nodes. Four clinically suspicious nodes were resected by palpation of the axilla, followed by axillary lymph node dissection, whether or not lymphatic mapping was successful. All the blue nodes and axillary node sampled labeled as SLN and ANS, respectively, were immediately submitted for histopathological lymph-node examination. The success rate, false negative rate, sens- itivity, accuracy of SLNB with subareolar injection were 84.9% (28/33), 13.6% (3/3+19), 86.4% (19/3+19) and 100%(28/28), respectively, compared with peritumoral injection 61.3% (19/31), 36.8% (7/7+12), 63.2% (12/7+12) and 100% (19/19). There were significant differences in the success rate, false negative rate, sensitivity, accuracy of SLNB with methylene blue existed between the two groups (p < 0.05). The sensitivity, specificity, accuracy, false negative rate of combination of SLNB and ANS was 100%, 52.3%, 67.2% and 0%, respectively, compared with SLNB 100%, 48.5%, 63.8% and 24.3%, irrespective of injection routes. Our results demonstrated the success rate of SLNB was higher with subareolar injection than peritumoral injection, and higher detection rate was obtained with combination of SLNB and ANS than SLNB only.Section Two: Detection of metastatic disease in SLNs and/or ANS was performed by Frozen Sections (FS), Rapid Immunohistochemistry (RAPID-IHC) and Reverse Transcriptase Polymerase Chain Reaction (RT-PCR). Three consecutive 5 um thick slices at 50 um interval were cut from two levels of tissue, one for H&E stain and the others for cytokeratin, muc1 immunohistochemistry (IHC), respectively. The remaining tissue after FS and RAPID-IHC of the LNs resected interoperatively was evaluated by RT-PCR. For 64 patients, a total of 348 lymph nodes were examined by FS, RAPID-IHC and RT-PCR. 37 patients had 139 lymph nodes metastases by FS, while 41 patients had 152 lymph nodes metastases by RAPID-IHC. RT-PCR demonstrated CK19 and mammaglobin expression in 3 lymph nodes undetectable by FS and RAPID-IHC, CK19, muc1 and mammaglobin expression in another 1 lymph node. The exquisite sensitivity of RT-PCR has hindered its clinical application because the majority of potential markers have some baseline expression in normal tissues, and the clinical consequence of the detection of micrometastases is not resolved. These results suggest that combination of FS and RAPID-IHC was somewhat superior to H&E in detecting micrometastases, but did not add anything to H&E concerning macrometastases. Further studies are needed to confirm the clinical utility of this strategy.