[Survival benefit of primary site surgery acquired by stage Ⅳ non-small cell lung cancer: a retrospective study based on seer database]

Objective: To investigate the value of primary site surgery in stage Ⅳ non-small cell lung cancer (NSCLC) and associated prognostic factors. Methods: The data of stage Ⅳ primary non-small cell lung cancer initially diagnosed from 2010 to 2015 were collected from the Surveillance, Epidemiology, and End Results (SEER) database and retrospective analyzed. Propensity-matched analysis was performed to decrease the selection bias between surgery and non-surgery groups. Overall survival (OS) and cancer-specific survival (CSS) were calculated by Kaplan-Meier curves. Log rank test and Cox regression analyses were applied to evaluate the prognostic factors. Results: A total of 4 657 patients were recruited. In the matched population, the median OS of surgery and non-surgery groups were 7 and 3 months. The 3-years OS were 14.6% and 5.0%, respectively. The 3-years CSS were 17.3% and 6.5%, respectively. Univariate and multivariate analyses indicated primary lesion surgery was an independent prognostic factor for OS and CSS (P<0.001). Subgroup analysis showed that patients with stage Ⅳ NSCLC who <80 years old, White and Black, gender, tumor located in the upper lobe and crossover, moderately and poorly differentiated, adenocarcinoma, T1-2 or T4 stage, N0 or N2, without regional lymph node dissection, without metastatic sites operation, and the number of metastatic organs<3, obtained a better 3-years OS and CSS from primary site surgery (P<0.05). Conclusion: Primary site surgery can significantly improve the OS and CSS of patients with stage Ⅳ NSCLC carefully selected.