Cisplatin, Pemetrexed Disodium, and Radiation Therapy Followed by Docetaxel in Treating Patients With Stage III Non-Small Cell Lung Cancer

DISEASE CHARACTERISTICS: * Histologic or cytologic diagnosis of non-small cell lung cancer (NSCLC), meeting 1 of the following staging criteria: * Stage IIIA disease, meeting all of the following criteria: * Mediastinal lymph node involvement * Greater than one mediastinal lymph node enlarged on CT scan, confirmed by positron emission tomography (PET) scan * Paralyzed left vocal cord with separate lung primary distinct from the aorto-pulmonary lymph nodes on the CT scan * Stage IIIB disease, meeting all of the following criteria: * N3 lymph node involvement * Enlarged N3 lymph nodes on CT scan confirmed by PET scan * Lymph node involvement may not extend to cervical lymph nodes other than supraclavicular lymph nodes * Right-sided primary tumor with left vocal cord paralysis * Evidence of tumor extension into the mediastinum and/or mediastinal structures by mediastinoscopy, bronchoscopy, or CT scan * No evidence of malignant pleural effusion unless effusion is only evident on CT scan * No more than 1 parenchymal lesions on the same or opposite sides of the lung * No brain metastases by CT scan or MRI PATIENT CHARACTERISTICS: * SWOG performance status 0 or 1 * Platelet count ≥ 100,000/mm³ * Absolute neutrophil count ≥ 1,500/mm³ * Creatinine ≤ 1.5 times upper limit of normal (ULN) * Creatinine clearance ≥ 45 mL/min * Bilirubin normal * Transaminases (SGOT and/or SGPT) ≤ 1.5 times ULN * Alkaline phosphatase ≤ 2.5 times ULN * Total lung volume (i.e., right and left lung minus the gross tumor volume) receiving greater than 20 Gy of radiation ≤ 40% * FEV\_1 ≥ 70% of predicted * DLCO ≥ 50 mL/min * No other concurrent malignancy * Prior malignancy allowed provided it is in clinical control and is not likely to impact clinical outcome in the opinion of the treating physician * No peripheral neuropathy ≥ grade 2 * No serious medical illness, including, but not limited to, any of the following: * Uncontrolled congestive heart failure * Uncontrolled angina * Myocardial infarction * Cerebrovascular event within the past 6 months * History of chronic active hepatitis * History of HIV infection * Active bacterial infection * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * Must be willing and able to take folic acid, cyanocobalamin (vitamin B12), or dexamethasone PRIOR CONCURRENT THERAPY: * No prior chemotherapy or radiotherapy for NSCLC * No concurrent participation in another therapeutic investigational study * Concurrent ibuprofen (400 mg four times daily) allowed during pemetrexed disodium administration provided the patient has normal renal function * No concurrent aspirin or other nonsteroidal antiinflammatory drugs (NSAIDs) 2 days before, during, and for 2 days after pemetrexed disodium administration * Patients on long-acting NSAIDs (e.g. naproxen sodium, diflunisal, nabumetone, or celecoxib) must be willing or able to discontinue usage 5 days prior to, during, and for 2 days after pemetrexed disodium administration