Inclusion Criteria:

- Histologically confirmed non-small cell lung cancer (squamous cell, adenocarcinoma,
poorly differentiated non-small cell carcinoma, or some combination of these); and

- Symptomatic patients (defined at discretion of investigator) for whom palliative
thoracic radiation is planned (3000cGy/10 fractions); and

- At least 18 years of age.

Exclusion Criteria:

- Previous erlotinib therapy; or

- Planned concurrent chemotherapy; or

- Expected survival of less than 3 months; or

- ECOG Performance Status of 3 or 4; or

- Multiple CNS metastasis or a single CNS lesion that has not demonstrated radiologic
stability (screening CT/MRI or head not required); or

- Granulocyte count <1,500/mm3, platelet count <100,000/mm3, or haemoglobin <9.0g/dl;
or

- SGOT (AST) or SGPT (ALT) > 2.5 times (x) upper limit of normal (ULN) in the absence
of known liver metastases or > 5 x ULN in case of known liver metastases; or

- Alkaline phosphatase (ALP) > 2.5 x ULN; or

- Serum bilirubin > 1.5 ULN; or

- Serum creatinine > 1.5 ULN or creatinine clearance < 60 ml/min; or

- Serum calcium beyond ULN; or

- Patients requiring systemic anti-fungal therapy, clarithromycin, phenytoin, or oral
anticoagulation therapy (see Appendix VI for complete list of medications); or

- A history of interstitial lung disease; or

- Known sensitivity to erlotinib; or

- Pregnancy, lactation, or parturition within the previous 30 days; or

- Unwillingness or inability to complete the required assessments of the trial; or

- Mental incompetence, including psychiatric or addictive disorders which would
preclude meaningful informed consent; or

- History of recurrent conjunctivitis or keratitis or other inflammatory changes of the
surface of the eye.

- Geographically inaccessible for treatment or follow-up evaluations; or

- Involved in an ongoing therapeutic trial.