DISEASE CHARACTERISTICS: Histologically or cytologically confirmed non-small cell lung cancer, including: Squamous cell carcinoma Adenocarcinoma (including bronchoalveolar cell) Large cell anaplastic carcinoma (including giant and clear cell carcinomas) Inoperable or unresectable stage IIIA or IIIB disease of the following stage groupings: T1 N2 M0 or T2 N2 M0 T3 N2 M0 and T4 N0-2 M0 eligible if staging is based on closeness to the carina or invasion of the mediastinum or chest wall Patients with contralateral mediastinal disease (N3) or tumors adjacent to but not invading a vertebral body are eligible if all gross disease can be encompassed in the study radiation boost field Patients with a transudate, cytologically negative, nonbloody pleural effusion are eligible if the tumor can be encompassed within a reasonable field of radiotherapy Measurable or evaluable disease