Gefitinib, Docetaxel, and Radiation Therapy in Treating Patients With Stage III Non-Small Cell Lung Cancer

DISEASE CHARACTERISTICS: * Histologically or cytologically confirmed non-small cell lung cancer (NSCLC), including any of the following: * Squamous cell carcinoma * Adenocarcinoma (including bronchoalveolar cell) * Large cell anaplastic carcinoma (including giant and clear cell carcinomas) * Stage IIIA/B disease * Unresectable disease * Tumors adjacent to a vertebral body allowed * No demonstrable bone invasion * All gross disease must be able to be encompassed in the radiation boost field in accordance with the homogeneity criteria * Contralateral mediastinal disease (N3) allowed if all gross disease can be encompassed in the radiation boost field in accordance with the homogeneity criteria * No scalene, supraclavicular, or contralateral hilar node involvement * Pleural effusion allowed if it is transudate, cytologically negative, and non-bloody AND tumor can be encompassed within a reasonable field of radiotherapy * No exudative, bloody, or cytologically malignant effusions * Pleural effusion seen on chest CT scan but not on chest x-ray and too small to tap allowed * Measurable disease, defined as lesions that can be accurately measured in ≥ 1 dimension (longest diameter to be recorded) as ≥ 20 mm with conventional techniques or as ≥ 10 mm with spiral CT scan * No nonmeasurable disease, including any of the following: * Bone lesions * Leptomeningeal disease * Ascites * Pleural/pericardial effusion * Abdominal masses that are not confirmed and followed by imaging techniques * Cystic lesions * Tumor lesions situated in a previously irradiated area PATIENT CHARACTERISTICS: * ECOG performance status 0-1 * Granulocyte count ≥ 1,500/mm\^3 * Hemoglobin \> 8.0 g/dL * Platelet count ≥ 100,000/mm\^3 * Bilirubin \< 1.5 mg/dL * Creatinine \< 1.5 times upper limit of normal (ULN) * Meets 1 of the following criteria: * AST and ALT \< 2 times ULN * AST and ALT ≤ 2.5 times ULN AND alkaline phosphatase (AP) normal * AST and ALT normal AND AP ≤ 4 times ULN * FEV\_1 ≥ 1.2 L * No other currently active malignancy except nonmelanoma skin cancers * Patients are not considered to have another currently active malignancy if they have completed therapy for the other malignancy and are considered by their physician to be at \< 30% risk of relapse (i.e., after treatment for early-stage prostate cancer) * Not pregnant or nursing * Fertile patients must use effective contraception during and for 3 months after completing treatment * No history of severe hypersensitivity reaction to docetaxel or other drugs formulated with polysorbate 80 * No known severe hypersensitivity to gefitinib or any of the excipients of this product * No evidence of severe or uncontrolled systemic disease (e.g., unstable or uncompensated respiratory, cardiac, hepatic, or renal disease) * No evidence of any other significant clinical disorder or laboratory finding that would limit compliance with study requirements * No evidence of clinically active interstitial lung disease (asymptomatic, chronic stable radiographic changes allowed) * No peripheral neuropathy ≥ grade 1 PRIOR CONCURRENT THERAPY: * At least 2 weeks since prior formal exploratory thoracotomy * No prior chemotherapy or radiotherapy for NSCLC * No prior epidermal growth factor-targeting drugs (i.e., gefitinib, erlotinib, or cetuximab) * No other investigational agent within 30 days of study entry * No concurrent phenytoin, carbamazepine, rifampicin, barbiturates, or Hypericum perforatum (St John's wort) * No other concurrent hormonal therapy or chemotherapy except for the following: * Steroids for adrenal failure, allergic reactions, or septic shock * Hormones for nondisease-related conditions (e.g., insulin for diabetes) * Glucocorticosteroids as anti-emetics