Factors associated with treatment given and survival outcomes in synovial sarcoma.
Authors: Singh Amisha , Thorpe Steven Walter , Keegan Theresa , Maguire Frances Belda , Malogolowkin Marcio H. , Abrahão Renata , Spunt Sheri L. , Carr-Ascher Janai R. , Alvarez Elysia Marie 
Published: June 2022

e23539 Background: Synovial sarcoma (SS) is a rare, high-grade soft tissue tumor and often requires multidisciplinary care with different treatment modalities. However, information on treatment patterns, especially in patients with localized disease and impact on survival is currently lacking. Methods: Adolescents and young adults (AYA, 15-39 years) and older adults (“adults,” ≥40 years) diagnosed with localized SS from 2000-2018 were identified in the California Cancer Registry. Treatment for SS consists of surgery and may also include chemotherapy and/or radiation. Multivariable logistic regression was used to identify clinical (e.g., tumor size) and sociodemographic factors (e.g., neighborhood socioeconomic status [SES]) associated with receipt of chemotherapy and/or radiation (versus none). Cox proportional hazards regression identified factors associated with overall survival (OS). Results are reported as odds ratios (OR) and hazard ratios (HR), respectively, with corresponding 95% confidence interval (CI). Results: There were 346 AYAs and 272 adults diagnosed with localized SS. Surgical resection occurred in 95% of patients. AYAs with tumors > 5 cm (vs. ≤5) were more likely to be given chemotherapy (OR 4.83, CI 2.66-8.79) as were adults with tumors > 10 cm (OR 5.21, CI 2.28-11.92). Adults ≥65 (vs. 60-65 years) were significantly less likely to receive chemotherapy (OR 0.11, CI 0.03-0.43). Adults living in high SES neighborhoods were more likely to receive chemotherapy (vs. low SES: OR 3.20, CI 1.40-7.31) or chemotherapy and radiation (OR 3.03, CI 1.24-7.41). In contrast, adults with public/no insurance were less likely to receive chemotherapy (OR 0.44, CI 0.20-0.95) or chemotherapy and radiation (OR 0.32, CI 0.13-0.79) than those with private insurance. There were no associations with age, insurance or SES and therapy given in the AYA patients. In AYAs, living in a low SES neighborhood (HR 2.28, 1.09-4.77) and tumor size > 5 cm (HR 2.01, CI 1.02-3.95) was associated with poor OS. In adults, older age (> 65: HR 3.34, CI 1.88-5.94), tumor size > 5 cm (HR 3.14, CI 1.92-5.15) and no surgical resection (HR 4.31, CI 1.54-12.06) was associated with worse OS. Treatment with chemotherapy and/or radiation was not associated with OS in either age group. Conclusions: In AYAs and adults with localized SS, tumor size impacted the likelihood of receiving treatment and influenced survival. Importantly, non-clinical factors, such as insurance and SES, also influenced the likelihood of receiving treatment among adults though they did not impact survival. Even in a population of patients with localized disease, living in a low SES neighborhood was associated with worse survival among AYAs. This underscores the impact of non-clinical factors in this population, and further research is needed to elucidate how these factors lead to disparities in care and to identify interventions to improve survival outcomes for these patients.