Effect of Pelvic Lymphadenectomy on Survival in Patients with Low-Risk Early-Stage Endometrial Cancer Diagnosed Intraoperatively Using Frozen Tissue Sections: A Retrospective Analysis

Purpose: To determine whether pelvic lymphadenectomy improved survival in patients diagnosed with low-risk early-stage endometrial cancer by intraoperative pathology. Methods: This retrospective analysis included 238 patients at our hospital. Results: The lymphadenectomy and non-lymphadenectomy groups contained 121 and 117 patients, respectively. In both groups, more than half the patients had tumor size >= 2 cm, and most had myometrial invasion <50%, stage Ia disease and no lymphovascular space invasion. Age, tumor size, myometrial invasion, surgical-pathologic stage and postoperative adjuvant therapy use were comparable between groups. The non-lymphadenectomy group had more patients treated laparoscopically (36.8% vs 10.7%; P<0.001) and fewer patients with histologic grade 2 disease (35.9% vs 62.8%; P<0.001) than the lymphadenectomy group. In the non-lymphadenectomy group, intraoperative frozen section pathology disagreed with postoperative pathology in only 31/117 cases for histologic grade (none upgraded to grade 3), 1/117 cases for myometrial invasion (one case revised from <50% to >= 50%) and 3/117 cases for surgical-pathologic stage (upgraded from Ia to Ib or II). Disease recurrence rate and overall survival did not differ significantly between the lymphadenectomy and non-lymphadenectomy groups. In multivariate Cox regression analysis, only surgical-pathologic stage >Ia (odds ratio, 47.7; 95% confidence interval, 6.7-340.8; P=0.031) was associated with increased odds of disease recurrence. Conclusion: Pelvic lymphadenectomy may not be necessary in patients with an intraoperative diagnosis of low-risk endometrial cancer.