Background: Ovarian clear cell carcinoma (OCCC) has a worse prognosis compared to other histological subtypes. Although the survival effect of lymph nodes ratio (LNR) on ovarian carcinoma have been elucidated in several studies, the prognostic effect of LNR in OCCC has not been separately studied. This study aimed to investigate the prognostic significance of LNR in FIGO stage III OCCC. Methods: Patients with FIGO stage III OCCC who underwent primary cytoreductive surgery and systematic lymphadenectomy from January 2008 to June 2014 in two independent hospitals were retrospectively reviewed. Two independent patients cohorts were used to investigate the survival impact of LNR by using Kaplan-Meier and Cox regression proportional hazard method. Results: In training cohort, the 5-year progression-free survival (PFS) rates was 32.4% for patients with LNR ≤ 25%, and 19.8% for patients with LNR > 25%, respectively (p = 0.017). The 5-year overall survival (OS) rates was 41.3% for patients with LNR ≤ 25%, and 25.8% for patients with LNR > 25%, respectively (p = 0.003). In multivariate analysis, increased LNR was correlated with a poorer DFS (HR = 2.12 ,95% CI 1.32-3.41, p = 0.002) and OS (HR = 2.29, 95% CI 1.37-5.12, p = 0.001). These results were verified in a validation cohort. Conclusions: LNR is an independent survival predictor in patients with FIGO stage III OCCC.
Keywords: lymph node ratio; ovarian clear cell carcinoma; survival.