Inclusion Criteria:

- Histologically or cytologically documented non-small cell lung cancer (NSCLC),
including squamous cell carcinoma, adenocarcinoma (including bronchoalveolar cell),
and large cell anaplastic carcinoma (including giant and clear cell carcinomas)

- ELIGIBLE DISEASE STAGES: Inoperable IIIA and selected IIIB

- Generally, patients entered must be considered unresectable or inoperable;
patients with T1 or T2, N2 disease are eligible; patients with T3, N2 or T4,
N0-N2 disease are eligible if based on the closeness to the carina, invasion of
the mediastinum or invasion of the chest wall; patients with T3, N0-N1 disease
are not eligible; patients must be M0 (M1 patients are not eligible)

- Patients with direct invasion of vertebral body are ineligible

- Patients with tumors adjacent to a vertebral body are eligible, unless
there is demonstrable bone invasion, as long as all gross disease can be
encompassed in the radiation boost field in accordance with the homogeneity
criteria

- Patients with contralateral mediastinal disease (N3) are eligible if all
gross disease can be encompassed in the radiation boost field in accordance
with the homogeneity criteria; patients with scalene, supraclavicular, or
contralateral hilar node involvement are ineligible

- Patients with a pleural effusion, which is a transudate, cytologically
negative and non-bloody, are eligible if the radiation oncologist feels the
tumor can be encompassed within a reasonable field of radiotherapy.
Patients with exudative, bloody, or cytologically malignant effusions are
not eligible; if a pleural effusion can be seen on the chest computed
tomography (CT) but not on chest x-ray (CXR) and is too small to tap, the
patient will be eligible; a pleural effusion appearing only after a
thoracotomy or other invasive thoracic procedure was attempted will not
make a patient ineligible

- PATIENTS MUST HAVE MEASURABLE DISEASE

- Lesions that can be accurately measured in at least one dimension (longest
diameter to be recorded) as >= 20 mm with conventional techniques or as ≥10 mm
with spiral CT scan

- Lesions that are not considered measurable include 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

- PRIOR THERAPY

- >= 2 weeks since formal exploratory thoracotomy.

- No prior chemotherapy or radiation therapy for NSCLC

- CTC performance status 0-2

- No "currently active" second malignancy other than non-melanoma skin cancers;
patients are not considered to have a "currently active" malignancy if they have
completed therapy and are considered by their physician to be at less than 30% risk
of relapse

- Non-pregnant and non-nursing because of significant risk to the fetus/infant

- No patients with uncontrolled intercurrent illness including, but not limited to,
ongoing or active infection, symptomatic congestive heart failure, unstable angina
pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would
limit compliance with study requirements

- No patients with chronic gastrointestinal disorders including liver disease,
diarrheal or emetic disorders, or malabsorptive conditions which could worsen
toxicity or limit efficacy of ZD1839

- No cytochrome P450 3A4 (CYP3A4) inducers within 7 days prior to starting protocol
therapy and while on protocol treatment. CYP3A4 inducers: phenytoin, carbamazepine,
barbiturates, rifampicin, dexamethasone, and St John's Wort; single doses of
dexamethasone used as an antiemetic are permitted

- No human immunodeficiency virus (HIV)-positive patients receiving combination
anti-retroviral therapy

- Granulocytes >= 1,500/ul

- Platelets >= 100,000/ul

- Calculated creatinine clearance >= 20 cc/min

- Bilirubin < 1.5 mg/dl

- Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase [SGOT]) < 2
x upper limit of normal (ULN)