The Association of Preoperative Prognostic Nutritional Index With Survival Outcome in Ovarian Clear Cell Cancer.

Background: The preoperative prognostic nutritional index (PPNI) has been investigated as a prognostic indicator in various cancers including epithelial ovarian cancer (EOC). However, its prognostic relevance in epithelial ovarian clear cell cancer (EOC-CC) remains uncertain. The objective of the study was to clarify the prognostic values of PPNI in EOC-CC patients.

Methods: We retrospectively reviewed 290 EOC-CC patients who underwent staging surgery at Rajavithi Hospital between January 2008 and December 2019. The PPNI was calculated using serum albumin × 10 (g/L) + 0.005 × peripheral blood lymphocyte count (per mm³). The association between PPNI and survival outcome was analyzed using the Kaplan-Meier method and the Cox proportional hazard model.

Results: The optimal cut-off value of PPNI, set at a mean of PPNI as 50, divided the EOC-CC patients into two groups: the low (n = 115) and the high (n = 175) PPNI group. With a median follow-up time of 63 months, patients with high PPNI exhibited significantly superior 5-year overall survival (OS) rates (76.4% vs. 56.8%, P = 0.004) and 5-year progression-free survival (PFS) rates (71.0% vs. 58.7%, P = 0.017) compared to patients with low PPNI. Univariate analysis revealed high PPNI correlated with increased OS (hazard ratio (HR): 0.51; 95% confidence interval (CI): 0.35 - 0.75) and PFS (HR: 0.63; 95% CI: 0.43 - 0.92). Nevertheless, in a multivariate analysis, high PPNI did not retain its status as an independent prognostic factor for a favorable prognosis in EOC-CC patients.

Conclusion: The present study did not confirm the prognostic significance of PPNI on survival outcomes in EOC-CC patients. Therefore, conducting prospective clinical research with large samples is necessary to illustrate the predictive values of PPNI in this rare disease.