This research study is studying a type of radiation therapy called Stereotactic Body Radiation Therapy (SBRT) as a possible treatment for stage IV non-small cell lung cancer (NSCLC) that has a mutated epidermal growth factor receptor (EGFR) or or displaced anaplastic lymphoma receptor tyrosine kinase (ALK) or ROS proto-oncogene 1 (ROS1) gene (= oncogene-driven NSCLC) and for which the subject has been receiving treatment with a targeted biological agent such as erlotinib, crizotinib, or other drugs.