The aim of this randomized study is to investigate pneumonitis, local tumor control, and survival outcomes of primary tumor radiotherapy omitting CTV for patients with advanced NSCLC responded to immunotherapy and chemotherapy

Studies have confirmed that systemic therapy combined with primary tumor radiotherapy can improve symptoms and prolong survival of advanced NSCLC. Our previous sturdy indicated that patients who received immunotherapy and subsequent radiotherapy suffered higher proportion of pneumonitis. Patients suffered grade 2 or more pneumonitis have worse prognosis. It is urged to optimize the radiotherapy dose and target volume for patients treated with immunotherapy and radiotherapy. According to retrospective and prospective studies, omitting primary tumor CTV radiation therapy showed no reduction in local control and survival for locally advanced NSCLC. It is postulated that omitting CTV radiation for patients responded to therapy with immunotherapy and chemotherapy will have less pneumonitis without sacrificing the local control rate. Omitting CTV may also retain better immune function which will facilitate the immunotherapy.

Inclusion Criteria:

1. Histologically or cytologically confirmed advanced non-small cell lung cancer (according to the 8th edition of the TNM cancer staging system of AJCC and UICC);
2. After over two cycles of chemotherapy combined with immunotherapy, the efficacy was CR, PR or SD (with a decreasing trend);
3. Age 18 to 80 years old, performance status 0-1;
4. measurable or evaluable lesions;
5. Survival expectancy is not less than 6 months;
6. adequate cardiac, pulmonary, renal, and hepatic and bone marrow function

Exclusion Criteria:

1. tumor progress after therapy with immunotherapy and chemotherapy
2. EGFR, ALK, or ROS1 mutation;
3. Previous thoracic radiotherapy;
4. grade 2 or more immune-related adverse events after induction immunotherapy
5. Previous malignancies (except stage I non-melanic skin cancer or cervical carcinoma in situ);
6. Pregnant or lactating women
7. undergoing other clinical trials;
8. Have serious comorbidities, including myocardial infarction, severe arrhythmia, severe cerebrovascular disease, ulcer disease, psychosis and uncontrollable diabetes;
9. Patients with HIV positive and undergoing antiviral therapy;
10. Active tuberculosis