A multicenter randomized phase II trial of stereotactic body radiotherapy for oligo-progressive non-small cell lung cancer. Eligible patients will be randomized in a 1:2 ratio between receiving their standard of care therapy or stereotactic ablative radiotherapy (SABR) to all sites of oligo-progressive lesions.Radiotherapy will be administered as soon as possible following randomization, and subjects will be followed until next disease progression. The primary outcome is progression-free survival (PFS).