Survival nomograms for patients with retroperitoneal soft tissue sarcoma based on the SEER database and an external cohort.

Background: Retroperitoneal soft tissue sarcoma (RPS) is a quite rare disease,and new nomograms need to be constructed to predict the overall survival (OS) and cancer specific survival (CSS) of RPS patients.

Methods: The clinical data of patients with RPS were extracted from the Surveillance, Epidemiology, and End Results (SEER) database and authors' hospital. The LASSO method and COX proportional hazard regression were used to screen independent risk factors which were used to develop nomograms.