Primary mobile vertebral column sarcomas: Prognostic factors vary by histologic subtypes.

BACKGROUND: Primary sarcomas originating from the mobile spine portends a particularly sinister outcome. Rarity of the disease process has resulted in inconsistent data due to small sample size and heterogeneity in patient selection and analytics. METHODS: Surveillance, Epidemiology and End Result (SEER) database from 1975 to 2017 was queried to report incidence and survival data in 712 patients in the United States. Kaplan-Meier and Cox Regression were used to determine the prognostic factors affecting survival. RESULTS: Incidence of spinal sarcoma was 0.019 per 100,000 persons in 2017 and has not significantly changed since 2000 (p > 0.05). Disease-specific 5-year survival for the entire cohort was 57%. Osteosarcoma has the worst 5-year survival (39%) and chondrosarcoma has the best 5-year survival (69%). Independent predictors of survival for the entire cohort included age, grade, and stage. Stage was an independent predictor of survival for every histologic subtype. Additional predictors of survival for spinal osteosarcoma, Ewing sarcoma, and chondrosarcoma included age, size, and grade, respectively. CONCLUSIONS: The current study is an analysis of a population-based registry reporting incidence survival data for patients with sarcoma of mobile vertebral column. Survival and prognostic factors vary by histologic subtypes. There is lack of improvement in survival over the last three decades.