After Institutional Review Board approval was obtained at University of Southern California, the institutional database for endometrial cancer was utilized to identify eligible cases. The database consists of consecutive patients with all histology type endometrial cancer who underwent hysterectomy-based surgical staging at Los Angeles County/University of Southern California Medical Center (January 2000 and December 2013) and the University of Southern California Keck Medical Center (December 2008 and December 2013). The case group consists of endometrial cancer patients with histopathologically confirmed LVSI in the hysterectomy specimen (LVSI-positive group). The control group consists of endometrial cancer with no LVSI in the hysterectomy specimen (LVSI-negative group). Cases receiving neoadjuvant chemotherapy or radiation, those with sarcoma, metastatic tumors to the endometrium, and endometrial hyperplasia were not included. Stage IV disease were also excluded. Among eligible patients for the case and control groups, the following information was abstracted from the medical records: (i) patient demographics, (ii) pathology results for hysterectomy-based surgical staging, (iii) treatment pattern for adjuvant therapy, and (iv) survival outcome. The STROBE guidelines were consulted for reporting in a case-control study [4 (link)]. Some of the patients in this study were within the context of our previous studies [20 (link)–24 (link)].