A Prospective Randomized Trial of Pre-Operative IMRT+Surgery Versus Surgery Alone For Primary Retroperitoneal Sarcoma

Inclusion Criteria: * Patients with primary retroperitoneal/pelvic soft tissue sarcoma. * Gross total resection (RO or R1) must be feasible. * No prior chemotherapy, immunotherapy or radiotherapy is allowable. * Patients should be over 18 years of age and capable of providing informed consent indicating awareness of the investigational nature of this trial, in keeping with hospital policy. * Karnofsky performance status of \>= 70 % * No other concurrent chemotherapy, immunotherapy or radiotherapy is allowable. * Adequate organ function defined as follows: absolute granulocytes \>= 1,500/mm 3, platelets \>= 150,000/mm 3, serum bilirubin \<= 1.5 mg/dl, serum creatinine \<= 1.5 mg/dl. * Written informed consent (study specific) must be obtained from each patient prior to entering the study. * Patients should be willing to be followed at Memorial Sloan-Kettering Cancer Center during the course of treatment and follow-up. * Patients must be able to get IMRT radiotherapy at Memorial Sloan-Kettering Cancer Center Exclusion Criteria: * Patients presenting with primary non-retroperitoneal soft tissue sarcoma or recurrent retroperitoneal sarcoma. * Patients who are deemed unresectable by clinical/imaging criteria. * Patients with histologic diagnosis of gastrointestinal stromal sarcoma, desmoplastic small round cell tumor, desmoid, Ewing's sarcoma, PNET, adenosarcoma, granular cell tumor, mesothelioma or rhabdomyosarcoma are excluded from the study. * Patients with known metastatic …