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.

OBJECTIVES: Primary * To assess whether the addition of radiotherapy to radiographically apparent residual disease after an initial course of standard chemotherapy results in an improvement in overall survival of patients with oligometastatic stage IV non-small cell lung cancer. Secondary * To compare the progression-free survival of patients treated with radiotherapy vs observation after standard chemotherapy. * To compare the time to disease progression and time to treatment failure in these patients. * To compare the confirmed response rate in these patients. * To compare the duration of response in these patients. * To compare the adverse events in these patients. OUTLINE: This is a multicenter study. Patients are stratified according to prior treatment with bevacizumab during first-line chemotherapy (yes vs no), number of standard chemotherapy courses (2-3 vs 4-6), Linear Analog Self Assessment value (≤ 7 vs \> 7), and histology (predominantly squamous cell vs not predominantly squamous cell). Patients are randomized to 1 of 2 treatment arms. * Arm I: Patients undergo observation for 6 weeks. * Arm II: Patients undergo radiotherapy 5 days a week for 6 weeks to all sites of gross disease. After completion of study therapy, patients are followed every 3-6 months for up to 5 years.