DISEASE CHARACTERISTICS:

• Histologically confirmed primary soft tissue sarcoma of the retroperitoneum or pelvis (e.g., iliac fossa)

  • The following histologies are eligible:

    • Alveolar soft part sarcoma
    • Anaplastic sarcoma
    • Angiosarcoma
    • Atypical lipomatous tumor (low-grade liposarcoma)
    • Clear cell sarcoma
    • Epithelioid sarcoma
    • Fibrosarcoma
    • Leiomyosarcoma
    • Liposarcoma (all subtypes)
    • Malignant fibrous histiocytoma
    • Malignant peripheral nerve sheath tumor
    • Myxofibrosarcoma
    • Neurofibrosarcoma
    • Spindle cell sarcoma
    • Synovial sarcoma
    • Unclassified sarcoma

  • The following histologies are not eligible:

    • Rhabdomyosarcoma
    • Extraosseous Ewing's sarcoma
    • Primitive neuroectodermal tumor
    • Osteosarcoma
    • Chondrosarcoma
    • Aggressive fibromatosis (desmoid tumor)
    • Gastrointestinal stromal tumor
    • Sarcomatoid carcinoma
    • Hemangiopericytoma

• Retroperitoneal sarcomas located predominantly in the retroperitoneum extending across the inguinal ligament into the abdominal wall are allowed provided that ≥ 90% of the tumor volume is located within the retroperitoneal space

  • No bowel obstruction OR history of previous bowel obstruction attributed to retroperitoneal tumor
• Primary non-visceral retroperitoneal masses consistent with sarcoma allowed provided diagnoses of carcinoma, melanoma, and lymphoma are excluded by immunohistochemistry
• Measurable gross disease by abdominopelvic CT scan (with IV and oral contrast) or MRI (with IV contrast)
• Patients must have undergone radiotherapy consultation within the past 30 days to confirm the feasibility of preoperative external-beam radiotherapy

• Patients must have undergone surgical consultation within the past 30 days to confirm and document the feasibility of macroscopically complete resection

  • No prior macroscopically incomplete (R2) resection (i.e., partial debulking or subtotal tumor resection with gross residual disease)
• No pelvic sarcoma extending through the sciatic notch

• No clinical or radiographic evidence of probable metastatic disease

  • Equivocal pulmonary or liver lesion allowed provided the likelihood of metastatic disease is small
• No sarcoma arising from bone or any retroperitoneal viscus (except the kidney)
• No sarcoma extending across the diaphragm into the thorax
• No recurrent retroperitoneal tumor
• No multifocal disease

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• ECOG 0-1 OR
• Zubrod 0-1

Life expectancy

• Not specified

Hematopoietic

• WBC ≥ 2,500/mm^3
• Platelet count ≥ 80,000/mm^3

Hepatic

• Bilirubin ≤ 1.5 times upper limit of normal (ULN)
• AST ≤ 2.5 times ULN
• Albumin normal* NOTE: *Higher levels allowed

Renal

• Creatinine normal
• BUN normal
• Functional kidney confirmed by intravenous pyelogram and/or differential renal isotope scan

Other

• Not pregnant
• Negative pregnancy test
• Fertile patients must use effective contraception during and for 3 months after study participation
• No other malignancy within the past 5 years (except effectively treated basal cell or squamous cell skin cancer) unless patient was curatively treated AND is at low risk for recurrence

PRIOR CONCURRENT THERAPY:

Biologic therapy

• Not specified

Chemotherapy

• No concurrent chemotherapy for primary tumor

Endocrine therapy

• Not specified

Radiotherapy

• No prior abdominal or pelvic irradiation
• No concurrent intraoperative or postoperative radiotherapy for primary tumor

Surgery

• See Disease Characteristics