Preoperative chemoradiation therapy for localized retroperitoneal sarcoma (RPS): Final results of a phase II study from the Italian Sarcoma Group.

10519 Background: To study the feasibility, safety and activity of the combination of high dose long-infusion Ifosfamide (HLI) and radiation therapy (RT) as preoperative treatment for resectable localized RPS. Methods: Patients received 3 cycles of HLI (14 g/m2). RT was started in combination with the onset of the 2nd cycle and administered up to a total dose of 50.4 Gy. Surgery was scheduled 4-6 weeks after the end of RT. Primary end-point was 3-yr relapse free survival (RFS). The expected 3-yr RFS in the study population treated with surgery alone was 40%. The experimental treatment was aimed at achieving a relative reduction in relapses of at least 1/3, corresponding to a 3-yrs RFS of 55%. With 60 enrolled patients, the study would have had a 90% power to discriminate between the hypotheses of 3-yrs RFS of 40% (H0) and 55% (H1), using a 1-sided 10% level of significance. Results: Between December 2003 and 2010, 86 patients were recruited. 3 patients were ineligible after central pathological review. 63...