SBRT for Oligoprogressive NSCLC After First Line Treatment With Immune Checkpoint Inhibitors

Inclusion Criteria: * Age at least 18 years; * ECOG PS 0-1; * Patients with pathologically confirmed stage IV NSCLC by tumor biopsy and/or fine-needle aspiration （AJCC the 8th Edition）; * Stable Disease for at least 6 months after first line immunotherapy; * Oligoprogressive disease in 5 or fewer lesions and 3 or fewer organs; * All oligopreogressive lesion ≤ 5cm, and intracranial lesion ≤3cm or 30cc; * Progressive disease would be amenable to SBRT and without indications for palliative radiotherapy in the opinion of the investigator; * Patients with a history of radiotherapy are eligible if radiotherapy administered more than 4 weeks before study entry; * Adequate organ function prior to enrollment: Adequate bone marrow function: white blood cell (WBC) count ≥ 3.0 \* 10 \^ 9/L or neutrophil count ≥ 1.5 \* 10 \^ 9/L, platelet count ≥ 100 \* 10 \^ 9/L and hemoglobin ≥90g/L,; Adequate hepatic function: total bilirubin, urea nitrogen and serum creatinine≤ 1.5 x upper limit of normal (ULN). Aspartate aminotransferase (AST) and Alanine aminotransferase (ALT) ≤2.0 ULN; * Life expectancy of more than 3 months; * Ability to understand and willingness to provide the informed consent and signed informed consent for the use of fresh tumor biopsies before and during the treatment; * Women of childbearing age and men must agree to use effective contraception during the trial. Exclusion Criteria: * History of another malignancy or concurrent malignancy (except for cured non-melanoma skin cancer, low-risk prostate cancer, T1/T2 glottic cancer, stage 0 or I breast cancer, non-invasive bladder cancer, cervical cancer in situ); * Positive for driver genes including EGFR, ALK, and ROS-1; * Mixed small cell with non-small cell lung cancer histology; * Malignant pleural or ascites; * Patients with brain metastasis require intracranial decompression; * Symptoms of spinal cord compression; * Severe autoimmune disease: inflammatory bowel disease (including Crohn's disease and ulcerative colitis), rheumatoid arthritis, scleroderma, systemic lupus erythematosus, Wegener's granulomatosis and related vasculitides; * Symptomatic interstitial lung disease or clinically active infectious/non-infectious pneumonitis. * History of another malignancy or concurrent malignancy; * Active infection, congestive heart failure, or any evidence of myocardial infarction, unstable angina pectoris or cardiac arrhythmia within 6 months prior to enrollment; * The patient is pregnant (confirmed by serum b-HCG if applicable) or is breastfeeding; * Mental disorders, drug abuse, and social condition that may negatively impact compliance in the investigator's opinion.