Intra-Operative Assessment of Sentinel Lymph Nodes with Touch Imprint Cytology – Experience on 232 Patients with Breast Cancer.

Abstract

Abstract IntroductionSentinel lymph nodes (SLNs) are generally evaluated by histology which takes about 3-5 days and axillary clearance is then carried out if SLN is positive for metastasis. This second operation to perform axillary clearance can be avoided, if a reliable intraoperative assessment is available. This will allow the surgeon to proceed to axillary clearance during the primary operation if intra-operative assessment of SLNs is positive. Touch imprint cytology (TIC), is a relatively new technique for intraoperative assessment. This study aimed to evaluate the accuracy and feasibility of TIC in our practice.MethodsThis was a prospective study of 232 patients with breast cancer. SLN biopsy was performed first and sent for TIC while surgeon proceeded with wide local excision or mastectomy. In pathology, nodes less than 5mm were bisected and others were sliced at 2mm intervals.Each cut surface was touched onto a slide allowing the weight of the node to release the cells onto the slide. The slides were assessed by dedicated breast pathologists and the results telephoned to theatre. If TIC was positive, axillary clearance was performed. Permanent histological sections were evaluated with hematoxylin and eosin stain and immuno-histochemical staining. The TIC results were compared with the final histology of the SLN. We calculated the accuracy, sensitivity, specificity, positive predictive and negative predictive value of TIC. The time required for intra-operative assessment was recorded prospectively in the last 30 patients. We also calculated the percentage of patients who were spared from having a second operation for axillary clearance based on the results of TIC.ResultsAccuracy of TIC was 90%. Sensitivity and specificity was 54% and 100% respectively. Positive and negative predictive value was 100% and 88% respectively. On final histology, 52 patients (22%) were node positive. TIC diagnosed metastasis in 28(54%) patients (95% Confidence Interval 0.39-0.67). Thus 28 patients (54%) avoided a second operation. Among patients with falsely negative TIC, micrometastasis was seen in 6/24(25%) patients and isolated tumour cells in 1/24(4%) patient. Average time from harvesting of the nodes to receiving of result of the TIC for each patient was 32 minutes (range 15-53). This was proportional to the number of nodes sent. Average time taken by cytopathologist was 15 minutes. Prolongation of operation time was seen in only 22% patients on an average by 7 minutes (range 2-15).ConclusionsTIC is a simple and feasible technique with prolongation of operation time seen in only 22% patients on an average by 7 minutes. It is a reliable technique with an accuracy of 90%. No patient was subjected to unnecessary axillary clearance. Patients should however be counseled preoperatively about chance of false negative results on TIC and need for a second operation. TIC avoided a second operation for axillary lymph node clearance in 54% patients and thus also avoided delay in the adjuvant treatment of these patients. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1030.