Cancer Statistics,（2020）states that low lung cancer survival rates reflect the large proportion of patients (57%) diagnosed with metastatic disease, for which the 5-year relative survival rate is 5%.With the development of three-dimensional radiotherapy technology, the wide application of comprehensive treatment concept, and the understanding of the relationship between different metastatic state and survival of stage IV NSCLC, prospective and retrospective studies have confirmed that systemic therapy combined with primary tumor three-dimensional radiation Treatment is more conducive to improving symptoms and prolonging survival than medication alone. Some retrospective analysises of stage III NSCLC, omitting clinical target volume of primary tumor with intensity modulated radiotherapy showed no reduction in local control rate and survival time.Omitted CTV in Ⅳ NSCLC patients with primary tumor radiotherapy can make smaller target area, which could push up most of the local stage of late Ⅳ NSCLC patients with primary tumor radiation dose. Prospective studies are needed to further clarify whether omission of target areas may affect local control time, survival time, and radioactive toxicity.
The aim of this randomized study is to investigate local tumor control, survival outcomes,and complications on patients of stage Ⅳ non small-cell lung cancer ,whom based on medication with concurrent primary radiotherapy omitting clinical tumor volume.