(P 128) THE IMPACT OF HISPANIC ETHNICITY IN PRESENTATION AND OUTCOMES OF PATIENTS WITH SYNOVIAL SARCOMA

Objective: Synovial sarcomas (SS) harbor a specific, balanced, reciprocal translocation t(X;18) leading to the oncogenic SS18-SSX fusion. It accounts for 5-10% of all soft tissue sarcomas, and there is a lack of information regarding the impact of race and ethnicity on its presentation and outcomes. Florida is currently not included in the SEER database, and it is the US's ninth-most diverse population, with a diversity index of 64.1% and with the sixth-highest Hispanic population among all states. Sylvester Comprehensive Cancer Center (SCCC) and Memorial Healthcare System (MHS) are two large oncology centers in South Florida that provide care for this rare type of tumor. We aimed to identify the impact of Hispanic ethnicity in SS.

Methods: We retrospectively reviewed all patients with a confirmed diagnosis of SS between January 2003 and January 2022 in SCCC and MHS. All data were retrieved from electronic medical records. SPSS Statistics was utilized, Fisher exact test and log-rank test were used for analysis. A two-sided p< 0.05 was considered statistically significant.

Results: A total of 73 patients had a pathologically confirmed diagnosis of SS, with information regarding ethnicity, during the time period evaluated, 45.3% were Hispanic, and 54.7% were non-Hispanic. The Hispanic group was comprised mainly of female patients (66%) with a median age of diagnosis of 44 years old, these findings were similar in the non-Hispanic group, where 55% were women, and the median age at diagnosis was 42 years old. Fewer patients identified themselves as Black within the Hispanic group (3%) compared to the non-Hispanic (22%) (p=0.016). The most common site of primary disease was the extremity in both groups (Hispanic 63% vs non-Hispanic 75%) (p=0.384). Most tumors were diagnosed with a size bigger than 5cm (Hispanic 57% vs non-Hispanic 65%) (p=0.577) and with pathology reporting a monophasic SS (Hispanic 45% vs non-Hispanic 50%) vs biphasic or poorly differentiated (p=0.061). Non-Hispanics had more poorly differentiated tumors (Hispanic 3% vs non-Hispanic 17.5%) (p=0.054). Hispanic patients did have fewer cases of metastatic disease at diagnosis (Hispanic 9% vs non-Hispanic 32%) (p=0.023). The median overall survival (mOS) among Hispanic patients was not reached in our study, and mOS among the non-Hispanic patients was 5 years (p=0.099).

Conclusion: In our study, the patients more commonly presented with large tumors (>5cm) in the extremity and monophasic histology, regardless of their ethnicity. Non-Hispanic patients more often had poorly differentiated tumors, metastatic disease at diagnosis, and a trend toward worse mOS. This study had limited power due to the limited number of patients, and further studies are needed to identify the presence of disease-related differences in these populations.