Intensity-Modulated Radiation Therapy in Treating Patients Undergoing Surgery for Stage IB, Stage II, or Stage III Soft Tissue Sarcoma

RATIONALE: Specialized radiation therapy that delivers a high dose of radiation directly to the tumor may kill more tumor cells and cause less damage to normal tissue. Giving radiation therapy before surgery may make the tumor smaller and reduce the amount of normal tissue that needs to be removed. PURPOSE: This phase II trial is studying the side effects of intensity-modulated radiation therapy and to see how well it works in treating patients undergoing surgery for stage IB, stage II, or stage III soft tissue sarcoma.