Development of A Nomogram for Predicting Survival of Patients 
with Primary Mediastinal Germ Cell Tumor Based on SEER Database

Primary mediastinal germ cell tumor (PMGCT) is a rare but occasionally highly invasive mediastinal tumor. At present, there are few related disease special survival (DSS) studies on PMGCT, rare large data analysis, and uncommon DSS prognostic models. This study was to investigate the prognostic factors of DSS of the PMGCT patients, and build a simple and effective nomogram to predict the DSS prognosis in patients with PMGCT. Retrospective clinicopathological data of 325 patients with PMGCT from 1975 to 2019 were extracted from Surveillance, Epidemiology, and End Results (SEER) database. The Kaplan-Meier method along with the Log-rank test were utilized to estimate the DSS. Cox proportional hazard regression model was used to screen the independent risk factors affecting prognosis, from which an individualized nomogram was constructed to predict 3-yr, 5-yr and 8-yr DSS of patients with PMGCT. The prediction accuracy of the model is evaluated by receiver operating characteristic (ROC) curve, correction curve an