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.

Eligibility Criteria:
DISEASE CHARACTERISTICS:

* Histologically or cytologically confirmed non-small cell lung cancer (NSCLC)

  * Mixed histology allowed if all components are consistent with NSCLC
  * Squamous cell histology allowed
* Stage IV disease

  * Oligometastatic disease (M1 with 1-3 metastases)

    * Patients with M1 disease that involves intrapulmonary metastases are eligible provided ≤ 40% of the total lung volume receives ≥ 20 Gy of radiotherapy
* Previously untreated disease OR achieved stable disease or partial response within 8 weeks after completion of 2-6 courses of standard platinum-based chemotherapy (administered every 3-4 weeks)
* Pleural effusion allowed provided it is minimal
* No history of or current brain metastases

  * Patients who have had up to 3 brain metastases allowed provided they have been treated with not signs of progression

PATIENT CHARACTERISTICS:

* ECOG performance status 0-1
* Life expectancy ≥ 12 weeks
* Platelet count ≥ 100,00/mm\^3
* Hemoglobin ≥ 9 g/dL
* WBC ≥ 2,000/mm\^3
* Creatinine ≤ 2 times upper limit of normal
* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception
* Able to undergo radiotherapy, based on radiation oncology consultation
* Willing and able to comply with study treatment
* FEV_1 ≥ 1 L
* No requirement for daily supplemental oxygen
* No second primary malignancy, except for any of the following:

  * Carcinoma in situ of the cervix
  * Nonmelanoma skin cancer
  * History of low-grade (Gleason score ≤ 6) localized prostate cancer, even if diagnosed within the past 5 years
  * Stage I breast cancer that was treated within the past 5 years
  * Other malignancy that was diagnosed and definitely treated ≥ 5 years ago with no subsequent evidence of recurrence
* No concurrent severe and/or uncontrolled medical condition, including any of the following:

  * Angina pectoris
  * Congestive heart failure within the past 3 months, unless LVEF \> 40%
  * Myocardial infarction within the past 6 months
  * Cardiac arrhythmia
* No clinically significant infection
* No psychiatric illness or social situation that would limit compliance with study requirements

PRIOR CONCURRENT THERAPY:

* See Disease Characteristics
* No prior therapy for this cancer other than 2-6 courses of standard platinum-based chemotherapy with or without bevacizumab
* No prior radiotherapy to the treatment sites (e.g., primary lesion, clinically involved nodes, or metastatic lesions)
* No bevacizumab during and for 4 weeks after completion of radiotherapy
* No concurrent systemic chemotherapy
* No other maintenance systemic therapy during radiotherapy
* No other concurrent investigational agents for the primary neoplasm
* No concurrent intensity modulated radiotherapy
* No concurrent prophylactic nodal radiotherapy