Regarding the assessment of patients’ immune and nutritional status, prognostic nutritional index (PNI) has been reported as a predictive marker for surgical outcomes in various types of cancer. The aim of our study was to evaluate the effect of PNI in prognosis of gastric cancer patients submitted to curative-intent resectional surgery.

A retrospective analysis with 637 gastric cancer cases submitted to curative-intent surgery, between 2010 and 2017, in an upper GI surgery unit. We analyzed 396 patients that met the inclusion criteria for this study. The median follow-up was 37 (0–113) months.

According to Youden’s method, the optimal PNI cutoff for OS was 41.625 (sensitivity 89.3% and specificity 41.3%). OS was significantly shorter in the lower-PNI group of patients when compared to the higher-PNI group (40.26 vs 77.49 months; p < 0.001). Higher PNI had a positive impact on OS in univariable analysis. When adjusted to pStage, higher PNI was still significantly associated with better OS (HR 0.405; CI 95% 0.253–0.649; p < 0.001). Regarding DFS, higher PNI was associated with better DFS (HR 0.421; CI 95% 0.218–0.815; p = 0.010). Higher-PNI group had a protective effect regarding postoperative morbidity and mortality.

In this cohort, PNI was disclosed to significantly impact GC patients’ OS and DFS, including in multivariable analysis when adjusting for classical prognostic features. PNI can be used to predict patients at increased risk of postoperative morbidity and mortality. This index may be of use in identifying candidate patients who would benefit from perioperative nutritional support to improve surgical outcomes.