Nie D, et al. - In patients with epithelial ovarian cancer (EOC), researchers examined the prognostic ability of the systemic immune-inflammation index (SII). In this retrospective study, 250 patients with EOC from West China Second University Hospital were assigned into the discovery cohort and 283 patients with EOC from The Affiliated Hospital of Southwest Medical University were assigned into the validation cohort. Advanced FIGO stage, lymph node metastasis, and tumor recurrence correlated with high SII. In univariate Cox regression, patients in both cohorts with high SII had a significantly shorter progression-free survival (PFS) and overall survival (OS) vs low SII patients. SII is an independent prognostic factor for EOC patients.