Evaluation Of Intraoperative Touch Imprint Cytology Of Axillary Sentinel Lymph Node Accuracy In Comparison To The Permanent Histology Diagnosis. A prospective study Of 25 Invasive Breast Cancers.

Background: Intraoperative evaluation of axillary sentinel lymph node (SLN) in patients with breast carcinoma reduces the need of re-operations for axillary lymph node dissection. Various methods such as touch imprintcytology (TIC) and frozen section histology (FS) have been used to determine the SLN status intra-operatively. The sensitivity of intraoperative TIC examination on SLN is not consistent and varies in different studies. The aim of this study was to determine the specificity and sensitivity of TIC, and its feasibility in clinical use.

Methods: A prospective study was conducted on 24 female and 1 male patients with histologically proven breast carcinoma and an at most clinical stage of cT2N0, between March 2017 and 2020. Axillary lymph nodes were not detected/palpable on physical examination. The patient underwent breast-conserving surgery i.e. quadrantectomy with sentinel lymph node biopsy. The intact lymph nodes were sent to histopathology laboratory for intraoperative TIC. The nodes were bisected, touch smears made and stained using the H&E and may Grunwald - Giemsa methods. The remaining tissue was processed in formalin fixed paraffin-embedded blocks and the slides were stained with H&E.

Results: In the three- year period (2017-2020), sentinel lymph node intraoperative touch imprint cytology was performed on 25 patients' lymph nodes with primary breast cancer and clinically negative axillary lymph nodes in Muscat Private Hospital, Muscat, Oman. The average age of the patients was 54.69 year. SLN- TIC revealed 88.9% sensitivity, 93.75% specificity, 11.1% false negative rate and 6.25% false positive with an overall accuracy 92%.

Conclusion: Touch imprint cytology has high sensitivity and specificity with an accepted accuracy. Intraoperative TIC is practical, time-efficient, and cost-effective procedure requiring minimal tissue preparation for SLN evaluation especially in clinical practice where FS is unavailable. Intraoperative touch imprint cytology can detect macrometastasis and micrometastasis to a lesser extent. Key words: breast carcinoma, sentinel node biopsy, intraoperative diagnosis, touch imprint cytology, micrometastasis.