A Study of Hypofractionated Radiotherapy for Limited Metastatic NSCLC Harboring Sensitizing EGFR Mutations After First Line TKI Therapy

Inclusion Criteria: * Newly diagnosed metastatic lung adenocarcinoma harboring sensitizing EGFR mutations (L858R, exon 19 deletion), and became oligometastatic disease after 3 months TKI, evaluated by PET/CT scan, brain MRI, and abdomen ultrasound (≤6 discrete lesions of disease, exclusive of the brain metastases, ≤3 lesions in the liver, ≤3 lesions in the lung); * All sites of disease must be amenable to definitive RT; * An intrathoracic lymph nodal station is considered 1 discrete lesion, according to IASLC lymph nodal station map; * Age 18 years or older; * ECOG Performance Status 0-2; * Adequate bone marrow, liver and renal function, as specified below: Absolute Neutrophil Count (ANC) ≥ 1.5 x 109/L; Hemoglobin ≥ 8 g/dL; Platelets ≥ 100 x 109/L; Serum total bilirubin ≤ 1.5 x upper limit of normal (ULN) ; AST and ALT ≤ 2.5 x ULN or ≤ 5 x ULN if liver metastases are present; Serum creatinine ≤ 1.5 x upper limit of normal or creatinine clearance ≥ 60ml/min for patients with creatinine levels above institutional normal; * For women of child-bearing potential, negative pregnancy test within 14 days prior to starting treatment; * Men and women of childbearing age must be willing to use effective contraception while on treatment and for at least 3 months thereafter; * Patients and their family signed the informed consents; Exclusion Criteria: * Received chemotherapy before TKI therapy; * Brain parenchyma or leptomeningeal disease; * Any site of disease that is not amenable to definitive RT; * Concurrent malignancies other than non-melanoma skin cancer that require active ongoing treatment; * Any medical co-morbidities that would preclude radiation therapy.