Primary sarcomas of the spine: population-based demographic and survival data in 107 spinal sarcomas over a 23-year period in Ontario, Canada

Background context Spinal sarcomas are a rare, heterogeneous group of mesenchymal tumors. Current literature reporting demographic variables and survival information is limited to small case series, and a single registry with variable treatment modalities and time periods. Purpose We report on population-level data regarding all spinal sarcomas diagnosed over a 23-year period in Ontario, Canada, for the purposes of calculating incidence and prevalence of these tumors. Secondarily, survival is assessed by tumor type as well as adjuvant therapies during this time period. Study design Retrospective Cohort Study Patient sample Population-based data from the Institute for Clinical Evaluative Sciences (ICES) between 1993 and 2015. Outcome measures Outcome measures include incidence and prevalence of spinal osteosarcoma, Ewing's sarcoma, and chondrosarcoma of the spine, as well as 2-, 5-, 10- and 15-year survival and prevalence of adjuvant therapies. Methods Utilizing population-based data from the Institute for Clinical Evaluative Sciences (ICES) between 1993 and 2015, ICD codes were searched and available data extracted for the purposes of reporting basic demographic information and calculation of Kaplan Meyer survival curves. Databases include the Ontario Cancer Registry, Discharge Abstract Database, Ontario Health Insurance Plan, National Ambulatory Care Reporting System, Registered Persons DataBase (death) were analyzed. Results One hundred and seven spinal sarcomas were identified, with a mean incidence was 0.38 sarcomas per million population per year, that was stable over time. The mean prevalence was 8.1 sarcomas per million population. The most common diagnosis was Ewing's sarcoma (48 [44.9%] patients), followed by chondrosarcoma (33 [30.8%] patients), and osteosarcoma (26 [24.3%] patients). Chondrosarcoma had the highest survival rates with 77.2% and 64.2% 5- and 10-year survival rates, respectively, followed by Ewing's sarcoma with 48.1% and 44.9% 5 and 10-year survival and osteosarcoma with 36.0% and 30.9% 5- and 10-year survival. Conclusions Spinal sarcoma is a rare disease with variable survival depending on the histologic diagnosis. This population-level study involves a heterogeneous group of patients with variable stages of disease at presentation and variable treatments. Our data fit with the published literature for survival for those treated conservatively and surgically. Our data show considerable improvement in 5- and 10-year mortality when compared with previous population level studies on earlier patient cohorts, likely reflecting improvements in systemic and surgical treatments.