Objective To identify the clinicopathological risk factors for pelvic lymph node (PLN) metastasis and to evaluate the predictive significance of these factors for lymphadenectomy in clinical early-stage endometrioid endometrial adenocarcinoma (EEA).

Methods Six hundred and twenty-one patients with clinical early-stage EEA (tumor confined to uterus, diagnosed preoperatively or intraoperatively) who underwent hysterectomy plus bilateral salpingo-oophorectomy plus pelvic and/or para-aortic lymphadenectomy between 1989 and 2006 in the Obstetrics and Gynecology Hospital of Fudan University were retrieved. The predictive value of the risk factors for PLN metastasis was analyzed.

Results The positive PLN metastasis rate was 3.9%. The 5-year disease-related mortality rate in the positive PLN metastasis group was 25%, whereas the rate in the negative group was 0.8%. The positive PLN metastasis rates were higher in patients with higher-grade tumors, deep myometrial invasion, cervical stromal involvement, and lymphovascular space involvement (LVSI). The sensitivity and specificity of old age (≥60 years), grade 3, cancer deep myometrial invasion, cervical stromal involvement, and LVSI in predicting the PLN metastasis were 25.0%, 41.7%, 70.8%, 20.8%, and 41.7%; and 79.1%, 88.4%, 85.6%, 95.6%, and 94.5%, respectively. The multivariate analysis revealed that the deep myometrial invasion and LVSI were independent risk factors for lymph node metastasis. Combined with these 2 factors as the diagnostic criteria, the negative predictive value and specificity were 97.3% and 89.1%, respectively.

Conclusion The patients with clinical early-stage EEA with PLN metastasis showed worse prognoses, although the metastasis rate was low. The deep myometrial invasion and LVSI combination were superior predictive criteria for the PLN metastasis. An accurate evaluation of these factors, both preoperatively or intraoperatively, will be beneficial to predict PLN metastasis and guide the operation.