Establishment and validation of a nomogram for predicting overall survival in patients with vulvar carcinoma based on the SEER database

Background: Vulvar carcinoma (VC) is a rare female gynecological malignancy, and optimizing prognostic factors for VC requires large-scale research containing various clinical indicators of patients. Our study attempted to develop and validate a detailed survival nomogram for predicting the overall survival (OS) probability in patients diagnosed with VC. Methods: Patients diagnosed with VC between 2004 and 2015 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Univariate and multivariate Cox regression analyses were performed followed by the construction of the nomogram for OS. The performance of this model was evaluated using the concordance index (C-index), area under the time-dependent receiver operating characteristics curve (AUC), net reclassification improvement (NRI), integrated discrimination improvement (IDI), calibration plots and decision curve analysis (DCA). In addition, the C-index, AUC and DCA of the model and the 2009 International Federation of Gynecology and Obstetrics (FIGO) staging system were compared. Results: A total of 6275 patients were randomly assigned to the training cohort (n=4392) and the validation cohort (n=1883). Multivariate analysis identified independent prognostic factors (p