Abstract
PURPOSE: Patients with gastric neuroendocrine neoplasms (GNENs) face elevated risks of second primary malignancies (SPMs), yet tools for personalized risk prediction are lacking. This study aimed to explore the risk factors associated with the development of SPMs in patients with GNENs and to establish a new competing-risk nomogram to predict the occurrence of SPMs. METHODS: We obtained clinical data for GNENs patients from the Surveillance, Epidemiology, and End Results (SEER) database covering the period from 2000 to 2015. Using Fine and Gray's proportional sub-distribution hazards model, potential risk factors for SPM development in GNENs' patients were identified. A competing-risk nomogram was then constructed to quantify the probability of SPMs' occurrence and was evaluated using the area under the receiver-operating characteristic (ROC) curves (AUC) and calibration curves. RESULTS: Among the 5160 GNENs patients, 18.7% developed SPMs during a maximum follow-up period of approximately 131 months (median 82 months). Independent risk factors for SPMs included age, marital status, tumor size, histopathological grade, disease extent, and T staging. The nomogram based on these factors demonstrated relatively strong predictive accuracy. CONCLUSION: This study identifies key risk factors for SPMs in GNENs patients and introduces a nomogram that effectively predicts SPM risk. This tool may help clinicians better assess patient risk and guide treatment decisions.