Surgery With or Without Radiation Therapy in Treating Patients With Primary Soft Tissue Sarcoma of the Retroperitoneum or Pelvis

OBJECTIVES:

Primary

• Compare progression-free survival of patients with primary soft tissue sarcoma of the retroperitoneum or pelvis treated with surgery with vs without preoperative radiotherapy.

Secondary

• Compare the toxicity and complications associated with these regimens in these patients.
• Compare the rate of microscopically complete surgical resection in patients treated with these regimens.
• Compare the overall survival rate of patients treated with these regimens.

OUTLINE: This is a randomized, multicenter study. Patients are stratified according to tumor grade (low [G1] vs intermediate [G2] vs high [G3/4]), tumor size (< 15 cm vs ≥ 15 cm), and tumor histology (liposarcoma vs non-liposarcoma). Patients are randomized to 1 of 2 treatment arms.

• Arm I: Patients undergo surgery.
• Arm II: Patients undergo preoperative radiotherapy once daily, 5 days a week, for 5.5 weeks. Within 28-63 days after the completion of radiotherapy, patients undergo surgery.

In both arms, treatment continues in the absence of disease progression or unacceptable toxicity.

Patients are followed at 28 days, 4 months, every 6 months for 5 years, and then annually for 5 years.

PROJECTED ACCRUAL: A total of 370 patients (185 per treatment arm) will be accrued for this study within 4.5 years.

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:

Chemotherapy

• No concurrent chemotherapy for primary tumor

Radiotherapy

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

Surgery

• See Disease Characteristics