Phase II study of neoadjuvant high-dose ifosfamide with concurrent radiotherapy followed by surgical resection in high-risk soft tissue sarcoma: A Spanish Group for Research on Sarcomas (GEIS) study.

10052 Background: High-dose ifosfamide (HDI) has shown promising activity as single agent in first-line chemotherapy for advanced soft tissue sarcoma (STS). The purpose of this study was to assess the activity and toxicity of a preoperative doxorubicin-free regimen of HDI given concurrently with radiotherapy (RT) and followed by surgery in patients (pts) with localized high-risk STS. Methods: Pts with localized > 5 cm grade 2-3 and deep STS of the extremities and trunk wall, ≤65 years, no prior chemotherapy and ECOG PS 0-1 were enrolled in this multicenter phase II study. Pts received 3 cycles of preoperative HDI at a dose of 12 gr/m2 by continuous infusion over 5 days every 3 weeks, with mesna and prophylactic GCSF support, and concomitant external beam RT to a total dose of 50 Gy, followed by surgical resection. Postoperatively, pts with pathological response received 2 cycles of HDI and those with positive surgical margins 16 Gy of RT. The primary study endpoint was pathologic response (≥ 95% pathologi...