Objective Isolated para-aortic lymph node metastases are rare in patients with endometrial carcinoma. We wanted to determine the reliability of macroscopic pelvic lymph node findings at surgery in predicting para-aortic space involvement in these patients.

Methods We identified all women with surgically treated endometrial carcinoma at our institution between January 2008 and February 2013 (n = 854). One hundred seventeen patients received pelvic-aortic lymphadenectomy. Lymph nodes were considered grossly positive based on size and morphology.

Results In patients who underwent comprehensive lymphadenectomy, grossly positive pelvic nodes predicted para-aortic metastasis with a sensitivity of 52.4% and specificity of 93.8%. The positive and negative likelihood ratios were 8.4 and 0.51, respectively. The predictive power of grossly positive pelvic nodes remained significant (odds ratio, 18; 95% confidence interval, 4.1–78; P < 0.0001) after correcting for deep myometrial invasion, poor tumor differentiation, and nonendometrioid histology as confounders. The whole sample of 854 patients was used for Bayesian calculations. The cutoff for a clinically useful test was set at the negative predictive value of 98.0%. The negative predictive value of the test (ie, grossly positive pelvic nodes at surgery in predicting the likelihood of para-aortic metastasis) was 99.7% for patients with superficial grade 1 to 2 endometrioid carcinomas and 98.0% for patients with deeply invasive grade 1 to 2 endometrioid carcinomas. For patients with grade 3 endometrioid and nonendometrioid carcinomas, the negative predictive values were 97.3% and 92.2%, respectively. For the whole study population, the value was 98.4%.

Conclusions When uterine factors are used for risk stratification of endometrial carcinomas, selective para-aortic lymphadenectomy, based on gross findings of pelvic nodes, is feasible for patients with grade 1 to 2 endometrioid carcinomas, regardless of the depth of myometrial invasion. Similarly, gross findings of pelvic nodes can be used to evaluate the need for para-aortic lymphadenectomy in the strategy of routine pelvic lymphadenectomy.