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 disease, or those with radiologically evident
metastases.

- Patients with clinically significant heart disease (NYHA Class III/IV), history of
active angina or myocardial infarction within 6 months, history of significant
ventricular arrhythmia requiring medication with antiarrhythmics or a history of
clinically significant conduction system abnormality. Patients with any of the above
conditions who are seen by a cardiologist at MSKCC and are found to be an acceptable
risk for surgery will be allowed to participate in this study.

- Patients with any active concurrent malignancy other than non-melanoma skin cancers
or carcinoma-in situ of the cervix. Patients with previous malignancies but without
evidence of disease for > 5 years will be eligible.

- Women who are pregnant.

- Patients currently participating in other clinical trials the requirements of which
may preclude their complete involvement in this study

- Patients with serious intercurrent infections or non-malignant uncontrolled illnesses