Clinical features, treatment, and outcome in 108 patients with localized, high-grade synovial sarcoma (SS)

10584 Background: There remains ongoing controversy in the treatment of localized SS, with no clear consensus on routine use of chemotherapy. Methods: Between 1986 and 2007, 93 adult (AP) and 15 pediatric (PP) patients were diagnosed with high grade, localized SS at 2 centres in Toronto. Clinical records and pathology reports were examined. Survival distribution functions were estimated by Kaplan-meier and compared using Log-rank test. Results: Median age for AP and PP was 36 (range 14–76) and 14 (range 0.4–18) years, respectively. Sixty-six (61%) patients had large tumours (> 5 cm), 7 (6.5%) had neuro-vascular invasion, and 10 (9.3%) had bone invasion. 76 (82%) AP and 8 (53%) PP received radiation (RT). 16 (17%) AP and 13 (87%) PP received chemotherapy. All patients underwent definitive surgery with gross total resection; 9 patients (8 PP) had positive margins. Some patients received neoadjuvant chemotherapy, and response was evaluable in 15 patients: 10 SD, 2 PR, 1 CR, 1 PD. Relapse occurred in 32 patients: 28 distant, 3 local only, 1 local + distant. With a median follow-up of 5.6 years, EFS and OS was 72 ± 4.6% and 82 ± 4.2%, respectively and was similar for AP and PP. Patients with tumours > 5 cm had significantly worse EFS (63 ± 6.5%) compared to patients with small tumours (88 ± 5.4%, p=0.02), as did those with bone invasion (47 ± 18 vs.75 ± 4.9, p=0.05). The effect of chemotherapy was assessed in the entire cohort. Of 29 who received chemotherapy, 9 (31%) relapsed, and of 79 who did not receive chemotherapy, 23 (29%) relapsed. In patients with tumours >5 cm, relapse occurred in 41% (7/17) of those who received chemotherapy compared to 37% (18/49) in those that received no chemotherapy. Conclusions: Patients with SS < 5 cm have an excellent chance of cure with surgery and RT. Large tumours and those with evidence of bone invasion have a poor outlook. It is unlikely that chemotherapy contributes to an improvement in survival in SS. No significant financial relationships to disclose.