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

Primary Objectives \- To estimate progression free survival (PFS) after locally ablative therapy and erlotinib in EGFR-mutant NSCLC patients who progressed on prior EGFR-TKI therapy Secondary Objectives * To evaluate local control of sites previously progressive on erlotinib following stereotactic radiosurgery (SRS) followed by erlotinib * To estimate overall survival (OS) after locally ablative therapy and erlotinib in EGFR-mutant NSCLC patients who progressed on prior EGFR-TKI therapy * To characterize the toxicity of SRS * To characterize the toxicity of erlotinib when preceded by SRS Exploratory Objectives * To explore if VeriStrat results at initial progression are associated with longer PFS or OS after study treatment * To explore if VeriStrat results following completion of SRS are associated with longer PFS or OS after re-initiation of erlotinib * To explore whether "poor" VeriStrat signatures ever turn to "good" signatures with the study therapy, and to explore PFS and OS of patients whose signature changes