Abstract 76P
Background
Thoracic synovial sarcoma (SS) comprises of only 1-2% of all SS, hence data pertaining to it is sparse. This site is unique due to the involvement of vital mediastinal structures and the need for expert surgical and medical management.
Methods
This is a retrospective study utilising the patient database maintained at our Sarcoma Medical Oncology Clinic. We included patients (pts) with thoracic SS registered between 2017 to 2022. SPSS 26.0 was used for statistical analysis; Overall Survival (OS) and Progression-free Survival (PFS) were assessed by Kaplan-Meier method.
Results
22 eligible pts were identified with 12 (54.5%) males, and median age of 34.5 years (16-54). Common symptoms were chest pain (10, 45.4%), dyspnea (9, 41%), cough (6, 27.2%). ECOG Performance Status was 1 in 12 (54.5%) pts, 2/3 in 9 (40.9%) and 4 in 1 (4.5%). 15 (68.2%) pts had metastatic, 3 (13.6%) had localised (L) and 4 (18.6%) had locally advanced (LA) disease. 8 were L/LA at baseline with median time to metastases of 26 (2.5-49) months. Mean tumor size was 9.6 centimetres (2-20). Primary sites were lung (n=10), mediastinum (n=6), chest wall (n=4), pleura, heart (n=1 each). Metastatic sites were lung (n=10), pleural effusion (n=3), mediastinum (n=3) and atypical sites as breast (n=1), brain (n=1), bone (n=1). SS18 rearrangement was present in 15 pts. Ifosfamide/doxorubicin was given as adjuvant treatment to 6 pts and neoadjuvant chemotherapy (NACT) to 8 pts; 2 pts received concomitant dexrazoxane. Predominant response to NACT was stable disease (4/8) and partial response (2/8). Median 2 (1-5) lines of treatment (LoT) included doxorubicin-based regimens in first-line (18/19) and others as in the table. Median OS was 41 (22-59) months in all, and 10 months in pts with upfront metastases (p=0.008). Table: 76P
Medical treatments received for thoracic SS
| Drug | n (%) | Median PFS months (range) | |
| First-line | Ifosfamide+/- doxorubicin High-dose ifosfamide | 18 (94.8) 1 (5.2) | 12 (9-14.6) |
| Second-line | Gemcitabine-docetaxel (GD) Pazopanib High-dose ifosfamide Doxorubicin | 4 (36.3) 4 (36.3) 2 (18.1) 1 (9) | 3 (2-3.9) |
| Third-line | Pazopanib Trabectedin High-dose ifosfamide Regorafenib | 3 (42.8) 2 (28.5) 1 (14.2) 1 (14.2) | 7 (3.4-10.5) |
| Fourth-line | Pazopanib Regorafenib Anlotinib Trabectedin | 1 (25) 1 (25) 1 (25) 1 (25) | 3 (1-4.9) |
| Fifth-line | GD Regorafenib | 1 (50) 1 (50) | not reached |
Conclusions
Thoracic SS affects young pts and presents with advanced disease. Survival is poorer in those with upfront metastases. Further data on subsequent LoT and use of dexrazoxane in this subset needs to be generated.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.