Abstract
INTRODUCTION: CIC-rearranged sarcomas (CRS) are rare tumors predominantly affecting young adults. Despite distinct biology, CRS are often treated like Ewing sarcomas with multi-agent chemotherapy, surgery, and radiotherapy, although the benefits of each remain unclear. We report the impact of treatment on response and survival. METHODS: This retrospective multicenter study included patients diagnosed with CRS between 2002 and 2023. Demographic, treatment, and outcome data were collected. Event-free (EFS) and overall survival (OS) were estimated using Kaplan-Meier analysis; risk factors were assessed via log-rank tests and Cox regression. Treatment response was assessed using RECIST. RESULTS: Among 27 patients (median age 21.5 years; range 8-83), 14 (52%) had localized and 12 (44%) metastatic disease (1 unknown). In the localized group, 6 (43%) received chemotherapy (Response: 2 complete, CR; 1 partial, PR; 1 mixed, MR; 1 stable, SD; 1 progressive disease, PD); 5 (36%) died-3 (21%) had received chemotherapy. Among metastatic patients, 10 (83%) received chemotherapy (1 CR, 5 PR, 2 MR, 1 PD); 9 died (one without chemotherapy). Local control was achieved in 12/14 (86%) localized and 7/12 (56%) metastatic patients. Only surgical resection was associated with improved OS (HR 0.13; p < 0.01) and EFS (HR 0.26; p < 0.01), particularly with R0 resection (EFS HR 0.23; p = 0.02). At median follow-up of 18 months, 2-year EFS was 56% vs. 8% (p = 0.02) and OS was 67% vs. 23% (p = 0.02) for localized vs. metastatic disease. CONCLUSION: Complete resection is critical in CRS. Chemotherapy benefit remains uncertain, underscoring the need for improved local control and novel, biology-driven therapies.