Radiation Therapy or Observation After Chemotherapy in Treating Patients With Stage IV Non-Small Cell Lung Cancer

RATIONALE: Radiation therapy uses high-energy x-rays to kill tumor cells. Sometimes, after chemotherapy, the tumor may not need more treatment until it progresses. In this case, observation may be sufficient. It is not yet known whether radiation therapy is more effective than observation after chemotherapy in treating non-small cell lung cancer.

PURPOSE: This randomized phase II trial is studying how well radiation therapy works compared with observation after chemotherapy in treating patients with stage IV non-small cell lung cancer.