Introduction The prognostic nutritional index (PNI) reflects the immuno-nutritional status of patients with cancer, estimated based on pre-operative lymphocyte counts and serum albumin levels. The PNI has been widely used to predict the prognosis of gynecologic cancer. However, endometrial cancer (EC) remains relatively understudied compared to ovarian and cervical cancers. Therefore, this study aimed to evaluate the prognostic value of PNI in patients with EC.

Methods Laboratory and clinicopathological data from 370 patients who were diagnosed with EC between January 2010 and December 2021 were reviewed. PNI was analyzed for correlations with recurrence and survival. The receiver operating characteristic curves were generated for the PNI. Optimal cut-off values were determined. Based on the results of the ROC curve analysis, the patients were grouped into high and low PNI groups. Differences in the clinicopathological characteristics between patients with high and low PNI were compared between the two groups. The effects of the prognostic factors were analyzed using univariate and multivariate Cox proportional hazards model.

Results The optimal cutoff value of the PNI was 52.74 for DFS (area under the curve: 0.817, p <0.001). Significantly more patients in the low PNI group experienced recurrence (30.6% vs. 5.2%, p <0.001) and cancer-related death (17.8% vs. 2.8%, p <0.001). In multivariate analysis, PNI were independent prognostic factors for both DFS and OS.

Conclusion/Implications Low PNI was significantly associated with worse clinical outcomes in patients with EC. Our findings demonstrate that the PNI may be clinically reliable and useful as a prognostic marker for patients with EC.