Real-world outcomes of metastatic clear cell sarcoma sequential chemotherapy

Abstract

Clear cell sarcoma is an ultra-rare chemoresistant subtype of soft tissue sarcoma. This retrospective analysis aimed to clarify the efficacy of palliative chemotherapy in CCS by assessing response rates, progression-free survival (PFS), and overall survival (OS) at a referral center. A retrospective analysis of palliative treatment was conducted on patients with CCS treated at the sarcoma unit from 1997 to 2023. Treatment responses were assessed using RECIST criteria, and the Kaplan–Meier method was used to calculate PFS and OS. The analysis covered 23 CCS chemotherapy-treated patients with 11 (47.8%) men. The median age at the palliative treatment start was 32 years (range 18-59). The median follow-up was 8.2 months. Four patients were referred to our centre for M1 disease, and 6 received perioperative chemotherapy and progressed during follow-up. In the first line, 14 patients received anthracycline-based chemotherapy (60.9%), five were treated with ifosfamide (HD-IFO), and four received other regimens. One patient (4.3%) achieved partial response (PR), and 12 patients (52.2%) achieved stable disease (SD) as the best response. Median PFS in 1 line was 2.79 months (95% CI: 2.04–8.38), and 1.76 months (95% CI: 0.72–6.97) in the second line. The median OS from first-line palliative chemotherapy was 8.2 months (95% CI: 6.2–14), and the second-line palliative chemotherapy mOS was 4.6 months (95% CI: 3.9–NA). Perioperatively anthracycline-pretreated worsened patients’ median PFS in the M1 setting. Poor responses to conventional chemotherapy were observed in CCS, indicating a need for further clinical trials in this indication.