Histopathology Discrepancy of Preoperative Endometrial Sampling and Final Specimen: How Does This Influence Selective Lymph Node Dissection?

Objective Preoperative histology is a major component in the perioperative selective lymph node (LN) dissection decision process. Discrepancy between preoperative endometrial sampling and final specimen histopathology is generally accepted. The goals of this project are to determine if discrepancy of histopathology is associated with alteration of adjuvant treatment or outcome. Materials and Methods We performed a retrospective cross-sectional analysis of all patients undergoing surgery for endometrial cancer at a single institution from 2010 to 2014. All patients had preoperative endometrial sampling. Histopathology discrepancy was evaluated for potential in variation of perioperative LN dissection. Criteria for not performing LN dissection was defined as preoperative endometrioid histology, grade 1 or 2 lesion, myometrial invasion of 50% or less, and primary tumor diameter 2 cm or less. Results A total of 352 patients were identified; 44 were excluded because of no preoperative pathology or no residual disease on final pathology. Discrepancy of histopathology was noted in 64/308 (20.8%; 95% confidence interval [CI], 16.2%-25.3%) patients. Preoperative endometrioid histology was noted in 272 patients, and 17/272 (6.3%; 95% CI, 3.4%-9.1%) had preoperative sampling reviewed as a grade 1 or 2 endometrioid lesion and final specimen was upgraded to grade 3. Downstaging occurred in 3/272 (1.1%; 95% CI, 0%-2.3%) patients with preoperative grade 3 lesion and final specimen demonstrated grade 1 or 2 disease. All 3 patients' primary tumor diameter was greater than 2 cm and therefore received LN dissection. Histopathological discrepancy that would alter perioperative LN dissection decision based on the aforementioned criteria occurred in 2/272 (0.7%; 95% CI, 0%-1.8%). Conclusions Despite a 20% discrepancy of preoperative and postoperative histopathology, discrepancy that would alter a perioperative decision for LN dissection occurs in only 0.7% of cases in this retrospective single-institutional experience. Myometrial invasion and tumor size may be more influential than histology in LN selection criteria.