Stereotactic Radiosurgery or Other Local Ablation Then Erlotinib in Epidermal Growth Factor Receptor (EGFR)

Inclusion Criteria: * Written informed consent * 18 years of age or older * Histologically or cytologically confirmed stge IV EGFR-mutant NSCLC * History of previous response to EGFR-TKI defined by a RECIST 1.1 criteria * Progressive disease following EGFR-TKI therapy * Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1 * Adequate organ and marrow function * Negative urine or serum pregnancy test for female patients * Patients who can have children must agree to adequate contraception Exclusion Criteria: * Unresolved chronic toxicities greater than 2, measured by CTCAE v4 * Treatment with any FDA approved or experimental cancer treatment following progression on EGFR-TKI * Any history of previous greater than grade 3 toxicity attributable to erlotinib * Pregnant or lactating female * Any previous radiation to sites of planned Stereostatic Radiosurgery * History of another malignancy * Concomitant anticancer therapy, immunotherapy, or radiation therapy (within 4 weeks) * Evidence of severe or uncontrolled systemic diseases * Known hypersensitivity reaction or idiosyncrasy to erlotinib * Psychological, familial, sociological, or geographical conditions * Any other condition in investigator's opinion jeopardize compliance with protocol