Prognostic Nomograms to Predict Overall Survival and Cancer-specific Survival in Sacrum/Pelvic Chondrosarcoma (SC) Patients: A Population-based Propensity Score-matched Study.

ABSTRACT

STUDY DESIGN: A longitudinal cohort study. OBJECTIVE: The objective of this study was to evaluate the prognostic factors and determine the difference between different surgery scopes. Nomograms were constructed and validated to predict overall survival (OS) and cancer-specific survival (CSS) of sacrum/pelvic chondrosarcoma (SC) patients. SUMMARY OF BACKGROUND DATA Chondrosarcoma is a bone malignancy which is reported to be resistant to both chemotherapy and radiotherapy. Therefore, surgery is the most preferred treatment method. However, this remains a great challenge due to the complex anatomy of the area. MATERIALS AND METHODS: Data from the Surveillance, Epidemiology, and End Results (SEER) database of patients with conventional SC between 1998 and 2016 was retrieved for analysis. Cox analysis was used to estimate the mortality hazards ratios among patients. Propensity score matching was used to compare different surgery scope. Nomograms were constructed to predict the OS and CSS of patients with SC. RESULTS: A total of 377 patients were included in this study. The cutoff value for tumor size was considered to be 118 mm. The concordance indices (C-index) value for nomogram predictions of CSS were 0.871. Following propensity score matching, 158 patients were selected for the second time and its result showed no significant difference between the scope of surgery. CONCLUSIONS: Tumor size was considered to be closely related to the outcome of SC. There is no significant difference in the scope of surgery and limb salvage can be considered. The nomograms can precisely predict OS and CSS in patients with SC. These could help clinicians to perform survival assessments and identify patients at high risk. LEVEL OF EVIDENCE Level IV.