Efficacy of intraoperative imprint cytology of sentinel lymph node in breast cancer

Objective: The most important determinant of patient outcome in cases of breast carcinoma is the regional lymph node status. Intraoperative assessment of sentinel lymph nodes (SLNs) allows the surgeon to perform axillary lymph node dissection in the same sitting if required. The commonly performed intraoperative methods for SLN evaluation are touch imprint cytology (TIC) and frozen section. The present study aimed to determine the sensitivity, specificity, and accuracy of TIC with histopathological diagnosis as gold standard. Material and Methods: The lymph nodes sent for intraoperative examination were bisected along the long axis and touched onto clean glass slides followed by Toluidine blue and rapid Papanicolaou staining. The imprints were reviewed and the interpretation was conveyed to the surgeon. Thereafter, the biopsy was fixed in 10% formalin followed by paraffin embedding with hematoxylin and eosin staining. The specificity, sensitivity, diagnostic accuracy, positive predictive value, and negative predictive value were evaluated with histopathological diagnosis as gold standard. Results: A total of 60 patients who underwent resection surgery were included in the study. Majority (36.7%) of patients were in the age group 41-50 years with a mean age of 48.1 +/- 10.6 years. There were 54 cases (90%) and 6 cases (10%) of invasive carcinoma of no special type (ductal) and lobular carcinoma, respectively. According to modified Bloom-Richardson scoring, the cases were categorized as Grade 1-6 cases (10%), Grade 2-36 (60%), and Grade 3-18 (30%). The sensitivity and specificity of TIC were 87.5% and 100%, respectively. The diagnostic accuracy of TIC in the diagnosis of metastasis in SLN was 90%. Conclusion: TIC is an easy-to-perform, cost-effective, rapid, and accurate technique for axillary lymph node evaluation, which also overcomes the need for a cryostat.