Imprint cytology of the sentinel lymph node in the assessment of axillary node status in breast carcinoma

Background. Intra-operative assessment of the sentinel lymph node (SLN) status may allow the surgeon to complete the breast cancer surgery in most patients in one sitting. We have studied the role of imprint cytology in the assessment of SLN status. Patients and methods. Imprint cytology of the SLN in 132 patients with invasive breast carcinoma was correlated with the histopathological assessment of the SLN and overall axillary nodal status. In 26 patients, the cytology was reported intra-operatively. Results. Imprint cytology reflected the status of the parent node well (sensitivity 86%, specificity 97%, positive predictive value (PPV) 92%, negative predictive value (NPV) 93%). Its ability to reflect the axillary status was also good (sensitivity 70%, specificity 97%, PPV 95% and NPV 83%) but somewhat diminished by the relatively high number of false-negative SLN in the study. Intra-operative assessment (sensitivity 86%, specificity 100%, PPV 100% and NPV 95%) did not reduce the accuracy of imprint cytology in predicting the SLN status and took a mean of 24.5 min. Conclusions. Imprint cytology is an accurate and relatively simple method for the assessment of the SLN and can be a useful intra-operative tool.