Accuracy of intra-operative frozen section in guiding surgical staging of endometrial cancer

Surgery consists the main treatment of endometrial cancer; however, decision of lypmhadenectomy is controversial. Intra-operative frozen section (FS) is commonly used in guiding surgical staging; nevertheless, there are different reports regarding its adequacy and reliability. Aim of this study is to assess accuracy of FS in predicting paraffin section (PS) results in patients with endometrium cancer. Data of 223 cases, who were operated for endometrial cancer at a tertiary hospital in 2012–2019, were analyzed retrospectively. Histological type, grade, tumor diameter, depth of myometrial invasion, and cervical and adnexal involvement in frozen and paraffin section were evaluated. Positive and negative predictive values and accuracy of frozen results in predicting paraffin results for each parameter was assessed. Statistical significance was taken as 0.05 in all tests. Accuracy of FS in predicting PS results were 76.23% for histology, 75.45% for grade, 85.31% for depth of myometrial invasion, and 95.45% for tumor diameter. Surgery, based on FS results, caused undertreatment in 4 patients, while metastatic lymph node ratios were found in only 35.3–50.0% of cases who had high risk parameters at FS. Our FS results have reasonable accuracy rates in predicting PS results, in comparison with the previous literature. However, even if the high risk parameters detected in FS predict PS accurately, absence of lymph node involvement in all cases with high risk parameters indicates that FS-based triage cannot prevent unnecessary lymphadenectomies.