Intraoperative evaluation of sentinel lymph nodes in breast carcinoma by imprint cytology, frozen section and rapid immunohistochemistry.

Sentinel lymph nodes (SLN) isolated in 40 patients of breast carcinoma (stage T(1)/T(2)) were evaluated intraoperatively by imprint cytology and frozen section. Rapid immunohistochemistry (IHC) was done in cases where both imprint smears and frozen sections were negative for any metastatic tumor deposits. The results of these different techniques were compared with postoperative paraffin sections taken as "Gold Standard." Nottingham modification of Bloom Richardson scoring system was used for grading the tumors. Further, the correlation of the SLN status with tumor size, grade, and lymphovascular invasion was studied. The sensitivity, specificity, and overall accuracy of imprint cytology were 91.7, 100, and 95% respectively, and those of the frozen section were 95.8, 100, and 97.5% respectively. Examination of multiple serial sections improved the sensitivity and overall accuracy of frozen section. Results of intraoperative rapid IHC were equivalent to final paraffin sections. Histological grade and lymphovascular invasion were in direct correlation with SLN metastasis (P < 0.05). The risk of lymphovascular invasion increased from 22.2% in grade I tumors to 85.7% in grade III tumors. SLN biopsy is a reliable method to evaluate the status of the axillary lymph nodes. Imprint cytology can be used reliably where the facility of frozen section is not available.