S0502 Imatinib Mesylate With or Without Bevacizumab in Treating Patients With Metastatic or Unresectable Gastrointestinal Stromal Tumor

This randomized phase III trial is studying imatinib mesylate and bevacizumab to see how well they work compared to imatinib mesylate alone in treating patients with metastatic or unresectable gastrointestinal stromal tumor.