Eligibility Criteria:
DISEASE CHARACTERISTICS:
* Microscopically confirmed non-small cell lung cancer
* Stage IB (T2, N0, M0), IIA (T1, N1, M0), IIB (T2, N1, M0 or T3, N0, M0), or IIIA (T1-3, N1-2, M0) disease
* Satellite lesions in one lobe (T4) (stage IIIB) allowed
* Meets 1 of the following criteria:
* Measurable disease, defined as ≥ 1 unidimensionally measurable lesion ≥ 10 mm in the longest diameter
* Evaluable disease, defined as lesions on chest CT scan that are not measurable (e.g., ill-defined masses or mediastinal or hilar adenopathy)
* No metastatic disease except peribronchial/hilar lymph nodes (N1) or ipsilateral/subcarinal mediastinal lymph nodes (N2)
* No N3 lymph nodes (e.g., contralateral mediastinal/hilar or supraclavicular/scalene) by CT scan or positron emission tomography (PET) scan AND mediastinoscopy
* No T4 primary tumor (e.g., mediastinal invasion)
* No malignant pleural effusion
* Nonmalignant effusions (i.e., negative cytology, non-bloody, and transudate) allowed
* Effusions visible only by CT scan and not large enough for safe thoracentesis allowed
* No exudative effusion, defined by 1 of the following criteria:
* Pleural fluid protein:serum protein ratio \> 0.5
* Pleural fluid lactic dehydrogenase (LDH):serum LDH ratio ≥ 0.6
* Pleural fluid LDH \> 200 IU/L
* No more than 1 area of fludeoxyglucose (FDG) uptake outside the area of the primary lung tumor OR evidence of malignant pleural disease as evidenced by pleural nodules by PET scan
* Single areas of FDG uptake will be further evaluated (e.g., by biopsy) for metastatic disease
PATIENT CHARACTERISTICS:
Age
* 18 and over
Performance status
* ECOG 0-1
Life expectancy
* Not specified
Hematopoietic
* WBC ≥ 3,000/mm\^3
* Platelet count ≥ 100,000/mm\^3
* Hemoglobin ≥ 9 g/dL
Hepatic
* Bilirubin ≤ 1.5 mg/dL
* SGOT or SGPT ≤ 1.5 times upper limit of normal
Renal
* Creatinine clearance ≥ 45 mL/min
Other
* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception during and for 3 months after completion of study treatment
* No other active malignancy within the past 2 years except nonmelanoma skin cancer or carcinoma in situ of the cervix
* No psychological, familial, sociological, or geographical situation that would preclude study compliance
PRIOR CONCURRENT THERAPY:
Biologic therapy
* Not specified
Chemotherapy
* No prior chemotherapy for lung cancer
Endocrine therapy
* Not specified
Radiotherapy
* No prior radiotherapy for lung cancer
Surgery
* No prior surgery for lung cancer
* At least 12 weeks since prior major surgery to the chest and abdomen
Other
* No concurrent aspirin or other nonsteroidal anti-inflammatory drugs for ≥ 2 days before (5 days for drugs with a long half-life \[e.g., naproxen, piraoxicam, difunisal, nabumetone, rofecoxib, or celecoxib\] or 8 days for long acting agents), during, and for 2 days after completion of each pemetrexed disodium administration
* No concurrent participation in another study involving chemotherapy or radiotherapy