Prognostic Value of the Pre-Treatment Prognostic Nutritional Index for Patients with Unresectable Locally-Advanced and Advanced Stage Upper Gastrointestinal Tract Cancer

PURPOSE: The prognostic nutritional index (PNI) is used to distinguish immune-nutritional status. Previous studies have shown that it is significantly associated with patient outcomes for various malignancies. This study aimed to evaluate the prognostic impact of PNI in patients with unresectable locally-advanced and advanced stage upper gastrointestinal tract cancer, including esophageal cancer and gastric cancer. METHODS: A retrospective study of 170 unresectable stage III–IV esophageal cancer and gastric cancer patients was conducted from January 2018 to December 2020. In our retrospective analysis, the pretreatment PNI of patients was calculated and analyzed. The Youden index was estimated to select the optimal cut-off value for PNI. Univariate and multivariate flexible parametric proportional hazards models with restricted cubic splines (RCS) were used to identify independent prognostic factors, and the Kaplan–Meier method was used to estimate survival curves. RESULTS: The median follow-up period was 5 months (ranging from 0.06 to 36.92 months). We determined 52.9 as the cut-off value by using the maximum Youden index. Subsequently, patients in the testing group were classified into high PNI and low PNI groups. Kaplan–Meier curves showed the low PNI group had significantly poorer overall survival (OS) than the high PNI group. Median OS in the low PNI group was 4.43 months compared with 8.23 months in the high PNI group (HR 2.42, 95% CI 1.33–4.40, p = 0.004). In the univariate analysis, low PNI, ECOG PS 2, and ECOG PS 3–4 were associated with OS. According to multivariate analysis, low PNI was an independent prognostic factor for OS (HR 2.31, 95% CI 1.24–4.29, p = 0.008). CONCLUSION: Pretreatment PNI is useful for independent prognosis of unresectable stage III–IV esophageal cancer and gastric cancer in patients.