RATIONALE: Diagnostic procedures, such as fludeoxyglucose F 18 positron emission tomography, may help find and diagnose cancer. It is not yet known whether standard diagnostic procedures are more effective when given with or without fludeoxyglucose F 18 positron emission tomography in finding cancer.

PURPOSE: This randomized clinical trial is studying fludeoxyglucose F 18 positron emission tomography given together with standard diagnostic procedures to see how well it works compared with standard diagnostic procedures alone in finding cancer in patients with a blood clot in a vein.

OBJECTIVES:

Primary

• Demonstrate the efficacy, in terms of increased numbers of cancer diagnoses, of PET-CT with 18-FDG in patients with idiopathic venous thromboembolism.

Secondary

• Assess the risk of cancer detected at 1 year.
• Assess whether PET allows earlier detection of cancer.
• Evaluate survival.

OUTLINE: This is a multicenter study.

All patients undergo standard (clinical and biological) diagnostic tests for cancer. Patients are randomized to 1 of 2 diagnostic arms.

• Arm I: Patients undergo diagnostic fludeoxyglucose F 18 PET in addition to standard methods.
• Arm II: Patients only undergo standard diagnostic methods. Patients are followed up for 2 years.

DISEASE CHARACTERISTICS:

• Diagnosis of idiopathic venous thromboembolism (IVTE) meeting 1 of the following criteria:

  • Newly diagnosed
  • Recurrent disease controlled by anticoagulant therapy

• No IVTE caused by a reversible major risk factor

• No IVTE caused by a major constitutional risk factor, including any of the following:

  • Antiphospholipid antibody syndrome
  • Antithrombin deficit
  • Protein C
  • Protein S

PATIENT CHARACTERISTICS:

• Not pregnant
• No other known active cancer at the onset of IVTE