Abstract: Objective：To investigate clinical factors affecting the concordance of intraoperative frozen section （FS） pathology and postoperative paraffin section（PS） findings in endometrial cancer. Methods：From Jul 1996 to Sep 2011，389 endometiral cancer patients undergoing treatment in Department of Gynecology，Renji Hospital，Shanghai Jiao Tong University and Department of Gynecology，Shanghai First Maternity and Infant Hospital，Tongji University were enrolled in this retrospective study. The results of intraoperative FS and postoperative PS findings were compared and clinical factors affecting concordance of tumor grade and tumor invasion were studied. Results：①According to the PS results，the overall concordance rate of tumor grade was 78.6%（147/182）. The concordance of G1，G2，G3 was 88.6%，60.6%，95.2% and respectively. With increasing tumor grade and deeper tumor invasion by PS diagnosis，the higher concordance of grade were observed（P=0.008，P=0.002）. ②The overall concordance rate of depth of myometrial invasion was 97.8%（178/182）. It was observed that the increasing grade of tumor cell by PS would result in decreased concordance rate in myometrial invasion between FS and PS（P=0.027）. Conclusions：The diagnosis depth of myometrial invasion by FS is relatively accurate. However，the clinical accuracy in tumor grade of FS might not be so satisfied.

Key words: Endometrial neoplasms, Frozen sections, Pathology, Paraffin sections