Intraoperative cytological assessment of sentinel lymph nodes in gynecologic cancer: diagnostic accuracy and limitations

Background. Intraoperative assessment of sentinel lymph nodes (SLNs) in patients with gynecological malignancies plays a key role in staging the disease and determining the extent of surgery. Cytological examination, is a valuable alternative to frozen section analysis due to its accessibility, efficiency, and minimal tissue requirements. Objective: to evaluate the sensitivity, specificity, and diagnostic accuracy of intraoperative cytological examination of SLNs in patients with early-stage endometrial and cervical cancers. Material and Methods. The study included 172 patients with clinically stage I endometrial (n=120) and cervical (n=52) cancer, who underwent surgery at the Department of Gynecological Oncology of the Cancer Research Institute, Tomsk National Research Medical Center. All patients underwent intraoperative cytological examination of imprint smears taken from the cut surface of SLNs. The results were compared with subsequent standard histological and immunohistochemical analyses. Results. In patients with endometrial cancer, the sensitivity and specificity of the cytological method were 93.4 % and 99.1 %, respectively. For cervical cancer, sensitivity was 50 % and specificity was 98 %. The overall diagnostic accuracy of intraoperative cytology in the cohort was 88 %. The main causes of false-negative and false-positive results were micrometastases, endosalpingiosis, and sinus histiocytic infiltration of lymph nodes. Conclusion. Intraoperative cytological evaluation of SLNs is a simple, rapid, and highly specific method for detecting macrometastases in gynecological cancers. Despite its limited sensitivity in detecting micrometastases, the method may be effectively used for intraoperative decision-making, particularly in resource-limited settings.