Clear cell sarcoma: The OSU experience.

Abstract

e23554 Background: Clear cell sarcoma (CCS) is an ultra-rare translocation-driven sarcoma. Often affects young adults with no sex preponderance, and whites have a higher occurrence. Frequently present as a slow-growing mass in the extremities or trunk. The EWSR1–ATF1/CREB1 mutation is pathognomonic. The optimal treatment has not been outlined, but it is extrapolated from soft tissue sarcomas. The role of systemic therapies still needs to be fully elucidated, largely due to limited data. This is one of the largest single-institution cohorts reported. Methods: Patients evaluated at The Ohio State University James Comprehensive Cancer Center between January 1, 2010, and April 1, 2022, were included. Data collected included baseline demographic variables, pathologic and molecular features, treatment regimen, and outcomes. Due to a small cohort size, descriptive statistics were performed instead of formal power calculations. Results: A total of five patients were identified. 3 of 5 were white (60%), and 2 of 5 patients were black (40%). The mean age at diagnosis was 46 years, median at 43 years, ranging from 29 to 66 years. 3 of the 5 patients were female (60%), and 2 were male (40%). The mean size of the tumor at presentation is 5.62 cm. 2 of the 5 patients had stage 1 disease at presentation (40%), one had stage 3 (20%), and 2 had Stage 4 (40%). 3 out of 5 patients received treatment with curative intent. 4 patients had primary in the abdomen/lower back or lower extremities (80%). 4 patients received chemotherapy, and these patients received 3 to > 5 cycles. 3 of the 4 on chemotherapy progressed (50%). A patient who received Sunitinib had the shortest time to progression, at 30 days (or 4.3 weeks). The patient who experienced the longest time to progression received Pazopanib, with progression occurring after 339 days (or 48 weeks). Within the early-stage patients, one of the three underwent surgery progressed (33.3%). None of the two patients that received radiation progressed (0%). 3 of 5 participants (60%) eventually expired during the study dates (2 with metastatic disease at diagnosis and 1 with localized disease). All patients received next-generation sequencing. One of these patients demonstrated positive expression levels for PD-L1. The median tumor mutation burden (TMB) value was 11.86 ranging from 2.06 to 28.16. Conclusions: We found that CCS has a high rate of disease progression despite the multimodality approach, and there is a high mortality associated with the disease. Due to the sample size of this single institution study, we cannot identify significant associations between clinical and demographic factors and treatment outcomes in clear cell sarcoma. However, these results stress the importance of multi-institutional (national and international) collaboration around ultra-rare subtypes of sarcoma to provide more significant patient data, improve outcomes, and design clinical trials for these patients.