Low Prognostic Nutritional Index is Common and Associated with Poor Outcomes Following Curative-intent Resection for Gastro-entero-pancreatic Neuroendocrine Tumors

Introduction: To investigate the impact of prognostic nutritional index (PNI) on short- and long-term outcomes of patients who underwent curative-intent resection for gastro-entero-pancreatic neuroendocrine tumors (GEP-NETs). Methods: Patients with GET-NETs who underwent curative-intent resection were identified from a multi-center database. The prognostic impact of clinicopathological factors including PNI on post-operative outcomes were evaluated. A novel nomogram was developed and externally validated. Results: A total of 2,099 patients with GEP-NETs were included in the training cohort; 255 patients were in the external validation cohort. Median PNI (n=973) was 47.4 (IQR 43.1-52.4). At the time of presentation, 1,299 (61.9%) patients presented with some type of clinical symptom. Low-PNI (& LE; 42.2) was associated with gastrointestinal symptoms, as well as nodal metastasis and distant metastasis (all p<0.05). Patients with a low PNI had a higher incidence of severe (& GE; Clavien-Dindo grade IIIa: low PNI 24.9% vs. high PNI 15.4%, p=0.001) and multiple (& GE; 3 types of complications: low PNI 14.5% vs. high PNI 9.2%, p=0.024) complications, as well as a worse overall survival (OS)(5-year OS, low PNI 73.7% vs. high PNI 88.5%, p<0.001), and RFS (5-year RFS, low PNI 68.5% vs. high PNI 79.8%, p=0.008) versus patients with high PNI (>42.2). A nomogram based on PNI, tumor grade and metastatic disease demonstrated excellent discrimination and calibration to predict OS in both the training (C-index 0.748) and two external validation (C-index 0.827, 0.745) cohorts. Conclusions: Low PNI was common and associated with worse short- and long-term outcomes among patients with GEP-NETs.