Incidence and prevalence of synovial sarcoma in the US: An analysis using SEER*Stat.

Abstract

e22535 Background: Synovial sarcoma (SS) is a rare and aggressive soft tissue sarcoma which primarily affects the extremities of the arms and legs, and can also occur in the head and neck, lungs and pleura, and the trunk. The disease burden of SS is generally extrapolated from overall soft tissue sarcoma (STS) with SS accounting for 4.5% of all STS (587 cases estimated in 2018 in the US) (Noone, 2018; Siegel, 2018). The objective of this study was to provide disease burden estimates specific to SS in the US. Methods: Data from the Surveillance, Epidemiology, and End Results (SEER) 18 Registries, Nov. 2017 (2000-2015) were analyzed using SEER*Stat software (v8.3.5). The incidence and prevalence of SS was estimated by utilizing SS-specific International Classification of Diseases for Oncology, V.3 (ICD-O-3) and histology codes. Data from 2011-2015 were used to project incidence rates (age-specific and age-adjusted), 5-year limited duration prevalence, number of incidence and prevalent cases, and the age distribution of synovial sarcoma for 2018. Results: In the US, the age-adjusted incidence rate of SS was 0.177 per 100,000 (estimated 580 incident cases) in 2018. SS is more frequently manifested in patients aged 20-49 years, with the highest occurrence of new cases in patients between 45-49 years (incidence rate 0.26 per 100,000). The prevalence rate of SS across all ages was 0.65 per 100,000 (estimated 2129 prevalent cases) as of January 1, 2018. Conclusions: We described incidence and prevalence rates of SS, including age-specific and age-standardized rates, and characterized the age distribution of SS. This approach provided more precise estimates that are specific to SS without extrapolation from STS, and which are not available in the literature.