Development and Validation of a Prognostic Nomogram for Gastroenteropancreatic Neuroendocrine Carcinoma: A SEER Database Analysis

Abstract

Abstract Background Gastroenteropancreatic neuroendocrine carcinoma (GEP-NEC) is a rare group of diseases with poor prognosis. This study aimed to develop and validate a prognostic nomogram to assess overall survival (OS) in patients with GEP-NEC. Methods Patients diagnosed with poorly differentiated GEP-NEC were collected from the Surveillance, Epidemiology, and End Results (SEER) database between 2011 and 2015 and divided into a training cohort and a validation cohort. Multivariate Cox regression analysis was used to identify independent prognostic factors. Nomogram was used to predict OS at 1 and 2 years. The nomogram was internally validated with validation cohort, and its predictive ability was evaluated using C-index, receiver operating characteristic (ROC) curves, calibration plots, decision curve analysis (DCA), and integrated discrimination improvement (IDI) index. Results A total of 887 patients were divided into the training group (n = 623) and the validation group (n = 264). Based on multivariate analysis, a nomogram was constructed with age, gender, N stage, tumor size, primary tumor resection, radiotherapy and chemotherapy (P < 0.05). The C-index was 0.701 (95% CI: 0.677–0.725) and 0.731 (95% CI: 0.698–0.764) for the training and validation groups, respectively. The C-index, ROC, IDI and DCA results indicated that this nomogram model has a good predictive value. Conclusions This study screened for seven independent prognostic factors for GEP-NEC. A nomogram model based on the seven variables provided visualization of the risk for each prognostic factor and could help clinicians predict the 1-year and 2-year OS of GEP-NEC.