DISEASE CHARACTERISTICS:

• Histologically confirmed desmoid tumor, meeting 1 of the following criteria:

  • Newly diagnosed disease

    • Not previously treated

    • Not amenable to complete surgical resection and/or radiotherapy

      • If surgical resection was attempted, there must be gross residual disease measurable by MRI

  • Radiographically documented recurrent or progressive disease

    • No prior chemotherapy or radiotherapy for the present recurrence

      • Tumors that progressed on prior chemotherapy are allowed provided patients have not received chemotherapy for this recurrence
• Measurable disease by gadolinium-enhanced MRI

• No other fibroblastic lesions or fibromatoses

  • Lipofibromatosis or desmoplastic fibroma of the bone allowed

PATIENT CHARACTERISTICS:

Age

• 18 and under at original diagnosis

Performance status

• Karnofsky 50-100% (patients over age 16) OR
• Lansky 50-100% (patients age 16 and under)

Life expectancy

• At least 8 weeks

Hematopoietic

• Absolute neutrophil count at least 1,000/mm^3
• Platelet count at least 100,000/mm^3 (transfusion independent)
• Hemoglobin at least 10.0 g/dL (transfusion allowed)
• No hemophilia
• No von Willebrand disease
• No other clinically significant bleeding diathesis

Hepatic

• Bilirubin no greater than 1.5 times upper limit of normal (ULN)
• ALT less than 2.5 times ULN

Renal

• Creatinine adjusted according to age as follows:

  • No greater than 0.4 mg/dL (≤ 5 months)
  • No greater than 0.5 mg/dL (6 months -11 months)
  • No greater than 0.6 mg/dL (1 year-23 months)
  • No greater than 0.8 mg/dL (2 years-5 years)
  • No greater than 1.0 mg/dL (6 years-9 years)
  • No greater than 1.2 mg/dL (10 years-12 years)
  • No greater than 1.4 mg/dL (13 years and over [female])
  • No greater than 1.5 mg/dL (13 years to 15 years [male])
  • No greater than 1.7 mg/dL (16 years and over [male]) OR
• Creatinine clearance or radioisotope glomerular filtration rate at least 70 mL/min

Cardiovascular

• No prior deep venous thrombosis
• EKG normal

Pulmonary

• Chest x-ray normal

Gastrointestinal

• No prior significant gastrointestinal hemorrhage
• No prior peptic ulcer disease

Other

• Not pregnant or nursing
• Fertile patients must use effective nonhormonal contraception
• No evidence of active graft-versus-host disease
• No allergy to aspirin

PRIOR CONCURRENT THERAPY:

Biologic therapy

• Recovered from prior immunotherapy
• At least 7 days since prior anticancer biologic agents
• At least 6 months since prior allogeneic stem cell transplantation
• More than 1 week since prior growth factors
• No concurrent immunomodulating agents

Chemotherapy

• See Disease Characteristics
• More than 2 weeks since prior myelosuppressive chemotherapy (4 weeks for nitrosoureas) and recovered
• No concurrent anticancer chemotherapy

Endocrine therapy

• No prior estrogen antagonists for desmoid tumor
• No concurrent hormonal contraceptives
• No concurrent steroids except for nontumor indications (e.g., asthma or severe allergic reactions)

Radiotherapy

• See Disease Characteristics
• Recovered from prior radiotherapy
• No concurrent adjuvant radiotherapy

Surgery

• See Disease Characteristics

Other

• No prior nonsteroidal anti-inflammatory drugs (NSAIDs) for desmoid tumor

• No concurrent NSAIDs for desmoid tumor

  • Occasional NSAIDs for musculoskeletal or other pain are allowed
• No concurrent participation in another COG therapeutic study