This phase II trial studies the safety and efficacy of aggressive thoracic radiotherapy in treating patients with non-small cell lung cancer that has not progressed after the first line systemic therapy. In this trial, patients with stage Ⅳ non small cell lung cancer who did not progress after first line systemic therapy will receive the aggressive thoracic radiotherapy, and the safety and efficacy of aggressive thoracic radiotherapy will be evaluated. The primary end points of the study are overall survival (OS), the secondary end points are local control rate, local progression free survival(LPFS), PFS, and toxicity and quality of life(QOL).

Inclusion Criteria:

• histologically or cytologically confirmed NSCLC
• stage IV disease
• no progression after first line systemic therapy
• 18 to 80 years of age
• Karnofsky performance status(KPS) score ≥70%
• no contraindications to radiation therapy
• presumed ability to tolerate thoracic radiation therapy to a BED≥53Gy

Exclusion Criteria:

• a history of thoracic surgery, radiation therapy, or more than first line chemotherapy
• pregnancy or lactation at the time of enrollment
• previous malignancy or other concomitant malignant disease