Maintenance Chemotherapy With or Without Local Consolidative Therapy in Treating Patients With Stage IV Non-small Cell Lung Cancer

PRIMARY OBJECTIVES: Phase II To evaluate the impact of adding local consolidative therapy (LCT) to maintenance systemic therapy versus maintenance systemic therapy alone on progression-free survival for patients with metastatic non-small cell lung cancer (NSCLC) with no evidence of progression and limited metastatic sites after first-line systemic therapy. Phase III To evaluate the impact of adding LCT to maintenance systemic therapy versus maintenance systemic therapy alone on overall survival for patients with metastatic NSCLC with no evidence of progression and limited metastatic sites after first-line systemic therapy. SECONDARY OBJECTIVES: I. To evaluate the impact of adding LCT to maintenance systemic therapy versus maintenance systemic therapy alone on in-field local failure. II. To evaluate the impact of adding LCT to maintenance systemic therapy versus maintenance systemic therapy alone on the time to development of new lesions. III. To evaluate the impact of adding LCT to maintenance systemic therapy versus maintenance systemic therapy alone on toxicity. IV. To evaluate the impact of adding LCT to maintenance systemic therapy versus maintenance systemic therapy alone on duration of maintenance systemic therapy usage. V. To evaluate the effect of adding LCT to systemic therapy in limited stage IV NSCLC on Quality of Life (QOL). VI. To collect biospecimens and evaluate the correlation between clinical outcomes and circulating tumor DNA (ctDNA). Patients are randomized 2:1 between the SBRT and chemotherapy vs. chemotherapy alone arms. After completion of study treatment, patients are followed up every 3 months for 2 years, every 6 months for 3 years, then annually thereafter.