Upper- versus lower-extremity synovial sarcoma: distinct surgical pathways and postoperative morbidity in a 24-year cohort

PURPOSE: Synovial sarcoma is a rare, late-relapsing soft-tissue sarcoma of the extremities. Whether anatomical location shapes the surgical treatment pathway, rather than prognosis alone, is unclear. We compared upper-extremity (UE) and lower-extremity (LE) tumors with respect to margin status, re-excision, reconstruction, morbidity and long-term oncological events. METHODS: Retrospective single-center cohort of 59 consecutive patients with histologically confirmed extremity synovial sarcoma treated between 2000 and 2023. Co-primary endpoints were a microscopically positive margin (R1) at the index resection and any postoperative complication within 8 weeks (Clavien-Dindo). Metastasis-free survival (MFS) and overall survival were exploratory. Fisher exact, Mann-Whitney U, Kaplan-Meier and log-rank methods were used; odds ratios (OR) are UE relative to LE. RESULTS: Twenty-three tumors were UE and 36 LE. R1 at the index resection was more frequent in UE tumors (14/23 [61%] vs. 5/36 [14%]; OR 9.64, 95% CI 2.73-34.1; P < 0.001), as was neoadjuvant therapy (39% vs. 8%; P = 0.007). Definitive R0 was achieved in all patients. Any postoperative complication (13% vs. 53%; OR 0.13, 95% CI 0.03-0.53; P = 0.002) and major complications (9% vs. 39%; P = 0.015) were more frequent after LE surgery. Seven of nine distant metastases occurred in LE tumors, several beyond six years; ten-year MFS was 90% versus 56% (log-rank P = 0.095). CONCLUSION: Upper- and lower-extremity synovial sarcomas followed distinct surgical pathways and carried distinct morbidity profiles, whereas definitive R0 resection was attained in both. The time-to-event findings are exploratory and require multicenter validation.