Background. The purpose of this study was to investigate various pathologic risk factors associated with para-aortic lymph node metastasis (LNM) in surgically staged patients with endometrial cancer. Materials and Methods. We performed a retrospective analysis of 203 consecutive patients with endometrial cancer who were surgically staged from 2000 to 2009. The association among the various pathologic variables for para-aortic LNM was determined with univariate and multivariate analyses. Results. Of 203 patients, 29 patients (14.3%) had LNM. Also, 10 patients (4.9%) had only pelvic LNM, 14 (6.9%) had both pelvic and para-aortic LNM, and 5 (2.5%) had para-aortic LNM without pelvic LN involvements. Histologic type (P = .001), tumor grade (P \ .001), tumor size (P = .003), depth of myometrial invasion (P \ .001), cervical invasion (P \ .001), parametrial invasion (P = .002), lymph-vascular space invasion (LVSI) (P \ .001), serosal/ adnexal invasion (P \ .001), positive cytology (P = .002), peritoneal seeding (P \ .001), and pelvic LNM (P \ .001) were significant pathologic factors for para-aortic LNM. On multivariate analysis, cervical invasion (P = .032), LVSI (P = .018), and positive pelvic LNs (P = .002) were independent factors for para-aortic LNM. With regard to isolated para-aortic LNM, tumor grade (P = .017) and LVSI (P = .002) were significant factors for LN involvements. On multivariate analysis, LVSI (P = .004) was the only significant independent factor. Conclusions. LVSI correlates significantly with the risk of isolated para-aortic LNM in endometrial cancer patients.Lymph node metastasis (LNM) is one of the important prognostic factors in endometrial cancer. The Gynecologic Oncology Group (GOG) published two large surgicalpathological studies of women with clinical stage I or II endometrial cancer.1,2 A substantial number of patients with clinical stage I disease (22%) had extrauterine disease, and tumor grade, depth of myometrial invasion, cervical invasion, vascular space invasion, positive cytology, adnexal involvement, and certain histologic types were found to be risk factors for pelvic and para-aortic LNM. Based on these results, the International Federation of Gynecology and Obstetrics (FIGO) adopted a surgical staging system to replace the clinical staging system in 1988.3 FIGO stage IIIC disease meant pelvic or para-aortic LN involvement. Several studies demonstrated that stage IIIC disease had diversity in the prognosis and patients with para-aortic LNM had poorer survival than those with negative paraaortic LNs.2,4-8 Recently, the FIGO revised the surgical staging system. 9 Stage IIIC disease was divided into two categories of IIIC1 with positive pelvic LNs and IIIC2 with positive para-aortic LNs, irrespective of the status of pelvic LNs status.Para-aortic LNM occurs mainly by way of pelvic LNM.4,10 However, direct spread to para-aortic LNs via ovarian vessels is a possible route of lymphatic spread, and patients have isolated para-aortic LNM without positive pelvic LNs. [10][11][12] ...