Low Prognostic Nutritional Index Is Common and Associated with Poor Outcomes following Curative-Intent Resection for Gastro-Entero-Pancreatic Neuroendocrine Tumors

Abstract

<b><i>Introduction:</i></b> 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). <b><i>Methods:</i></b> 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. <b><i>Results:</i></b> 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 (<i>n</i> = 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 (≤42.2) was associated with gastrointestinal symptoms, as well as nodal metastasis and distant metastasis (all <i>p</i> < 0.05). Patients with a low PNI had a higher incidence of severe (≥Clavien-Dindo grade IIIa: low PNI 24.9% vs. high PNI 15.4%, <i>p</i> = 0.001) and multiple (≥3 types of complications: low PNI 14.5% vs. high PNI 9.2%, <i>p</i> = 0.024) complications, as well as a worse overall survival (OS)(5-year OS, low PNI 73.7% vs. high PNI 88.5%, <i>p</i> < 0.001), and RFS (5-year RFS, low PNI 68.5% vs. high PNI 79.8%, <i>p</i> = 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. <b><i>Conclusions:</i></b> Low PNI was common and associated with worse short- and long-term outcomes among patients with GEP-NETs.