Image-Guided Radiation Therapy in Treating Patients With Primary Soft Tissue Sarcoma of the Shoulder, Arm, Hip, or Leg

RATIONALE: Image-guided radiation therapy uses high-energy x-rays to kill tumor cells. Specialized radiation therapy that delivers a lower dose of radiation directly to the tumor may kill more tumor cells and cause less damage to normal tissue. PURPOSE: This phase II trial is studying the side effects and how well image-guided radiation therapy works in treating patients with primary soft tissue sarcoma of the shoulder, arm, hip, or leg.