1686PThe final outcomes of study on combined therapy of adult patients with localized synovial sarcoma

Abstract Background Synovial sarcoma is a high-grade, malignant soft tissue sarcoma (STS) considered as relatively chemosensitive tumor, with particular sensitivity to ifosfamide. The aim of this prospective study was to analyze outcomes of patients (pts) with localized synovial sarcoma treated in a single institution with uniform neo- and adjuvant combined therapy protocol. Methods One hundred and seventy one pts (96 women and 75 men) with localized synovial sarcoma were treated at our institution between 1997 and 2014. Chemotherapy consisted of 4 cycles of ifosfamide 12 g/m2 (2 cycles given preoperatively) and two cycles of doxorubicin-based regimen 75 mg/m2. Most pts received neoadjuvant hypofractionated radiation therapy followed by immediate surgery. At a median follow-up of 114 months (range, 3 to 244 months) 69 deaths were recorded. Results Median age at diagnosis was 33 years (range 17-69). The most common localization was lower limb (n = 121), followed by upper limb (n = 32). Tumors larger than 5 cm in size were found in 70% of pts (median 8 cm; range 2 – 30 cm). Seventy-seven cases (45%) had primary diagnosed tumor. Sixty-four (37%) pts were referred to our institute after unplanned tumor excision and 30 (18%) pts because of clinical local recurrence. At the time of analysis, 36 (21%) pts had local recurrence (only 8% of pts with primary tumor) and 76 (44%) pts developed metastases. Median disease-free survival was 82 months. The 5-year overall survival (OS), local recurrence-free survival (LRFS) and distant recurrence-free survival (DRFS) rates were 74%, 80% and 60%, respectively. By univariate analysis, unplanned tumor excision (p = 0.0025) and positive margins (p = 0.048) were related to higher risk of local recurrence. In multivariable Cox’s regression, age >35 years (p = 0.045), male sex (p = 0.001), stage IIIB (p