Development and Validation of Prognostic Nomogram for Patients With Small Intestinal Neuroendocrine Carcinoma

Abstract

Small intestinal neuroendocrine carcinomas (SI NECs) are diagnosed very rarely, and the prognosis is extremely poor due to the metastatic disease of most patients at the time of diagnosis. This study aimed to establish nomogram models for prognostic evaluation of SI NEC in both overall survival (OS) and cancer-specific survival (CSS). Patients diagnosed with SI NEC between 2010 and 2015 were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database and further randomly divided into the training and validating cohorts at a ratio of 7:3. Univariate and multivariate cox analysis was conducted to determine significant variables for construction of nomogram. The performance of the nomogram models were then assessed by concordance index (C-index), calibration plot and the area receiver operating characteristic (ROC) curve (AUC). A total of 1110 patients were retrospectively selected from the SEER database. Multivariate models revealed that age, tumor grade, American Joint Committee for Cancer (AJCC) stage, surgery and chemotherapy all showed a significant association with OS and CSS. The discrimination of nomogram for OS prediction was superior to that of the 7th AJCC Tumor-Node-Metastasis (TNM) staging system (C-index = 0.798, 95% CI, 0.762 - 0.833 vs 0.623, 95% CI, 0.580 - 0.666, P < 0.001). Similar results were also observed in CSS nomogram. Well-corresponded calibration plots were noticed using the nomograms. The comparisons of AUC values showed that the established nomograms exhibited better discrimination power than 7th TNM staging system for OS and CSS prediction. In conclusion, we have successfully established novel nomograms for predicting OS and CSS in patients with SI NEC, which can assist clinicians in making predictions about individual patient survival and provide improved treatment strategies.