Introduction/Background*Endometrial cancer (EC) is the most common gynecologic malignancy in developed countries and the main treatment consists of surgery . Myometrial invasion is commonly used in guiding surgical extent and can be evaluated by intraoperative assessment (IOA). There are studies that show different reports regarding its adequacy and reliability. The aim of this study was to assess the diagnostic accuracy of IOA comparing with definitive histopathologic report surgically resected EC.

Methodology We analysed retrospectively all patients submitted to surgical staging for presumed EC with a definitive diagnosis of endometrioid carcinoma grade 1 and 2 at a tertiary hospital in 2017-2020. Results of IOA were compared to the final pathology report. The accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the IOA were calculated.

Result(s)*A total of 97 patients underwent surgical staging for EC. We had 41 women with histologically confirmed endometrioid carcinoma in which 39 were performed the IOA. The IOA had an accuracy of 82,1%, sensitivity of 64,3%, specificity of 92%, PPV of 81,8% and NPV of 82,1% in predicting miometrial invasion. In the definitive histopathological report 26 patients were classified with stage IA and 13 with stage IB. In the 27 cases identified as stage IA in IOA, the pathology reported stage IB in 4/39 (10,2%). 11/39 (28,2%) cases were identified as stage IB in IOA, and only 2/39 (5,1%) were in fact stage IA in the final pathology report. Surgery, based on the result of the IOA, caused undertreatment in 4/39 (10,2%) and overtreatment in 2/39 (5,1%) patients.

Conclusion*Our IOA results have reasonable accuracy rates in predicting malignancy. However, the concordance of tumor myometrial invasion between IOA and pathology report was suboptimal, leading to the need of a secondary surgery in some patients.