Patients with stage IV non-small cell lung cancer (NSCLC) comprise a heterogeneous group, and the optimal treatment for this group of patients is complex and debatable. We aimed to assess the effect of local thoracic therapy combined with chemotherapy on cancer specific survival (CSS). To evaluate the CSS of four subgroups of patients with stage IV NSCLC according to four different treatment modalities: combined modality of Chemotherapy, Surgery, and Radiation (Chem+Sur+RT), Chemotherapy and Radiation (Chem+RT), Chemotherapy and Surgery (Chem+Sur), and Chemotherapy only (Chem Only) by analyzing the Surveillance, Epidemiology, and End Results (SEER)-registered database. Kaplan-Meier methods were adopted and multivariable Cox regression models were built for the analysis of survival outcomes and risk factors. The 3-year CSS was 33.5% in "Chem+Sur+RT" group, 9.3% in "Chem+RT" group, 42.7% in "Chem+Sur" group and 11.8% in "Chem Only" group, which had significant difference in univariate log-rank test (P<0.001) and multivariate Cox regression (P<0.001). Moreover, we observed significant survival benefits in "Chem+Sur" group in all stage of T/N categories, including stage I, stage II, stage IIIa and stage IIIb (all P<0.001). Multimodality therapy, especially combined thoracic surgery and chemotherapy is associated with dramatically improved prognosis for patients with stage IV NSCLC.