Radiation in Stage I or Stage II Non-Small Cell Lung Cancer That Cannot Be Removed by Surgery

DISEASE CHARACTERISTICS: * Histologically or cytologically confirmed non-small cell lung cancer (NSCLC) * Stage I or II peripheral disease * T1, N0, M0 * T2 (≤ 5 cm), N0, M0 * T3 (≤ 5 cm, chest wall primary tumor only), N0, M0 * No T2-T3 primary tumors \> 5 cm or any T1-T3 tumor of the mainstem bronchus involvement * No T1-T3 tumor in the lung apex (i.e., tumor in a position that will result in irradiation of the brachial plexus to the prescribed dose) * Hilar or mediastinal lymph nodes ≤ 1 cm considered N0 * Any of the following primary cancer types: * Squamous cell carcinoma * Adenocarcinoma * Large cell carcinoma * Bronchioloalveolar cell carcinoma * Non-small cell carcinoma not otherwise specified * Underlying physiological medical condition that prohibits surgery due to a low probability of tolerating general anesthesia, the operation, the postoperative recovery period, or the removal of adjacent functional lung (i.e., medically inoperable) * Cytologic specimens obtained by brushing, washing, or needle aspiration of defined lesion allowed * If sputum cytology alone is used for diagnosis, it must be confirmed on a second specimen * Must develop a radiotherapy plan that meets the dose-volume constraints for critical organs * No ataxia telangiectasia PATIENT CHARACTERISTICS: * ECOG performance status 0-2 * Not pregnant or nursing * Able and willing to complete a quality of life questionnaire unless not literate in eit…