Effects of primary tumor resection on the survival of patients with stage IV extrathoracic metastatic non-small cell lung cancer: A population-based study

Abstract

BackgroundSelected non-small cell lung cancer (NSCLC) patients with extrathoracic metastases might benefit from surgical intervention; however, the evidence is limited. We investigated the benefit of surgery in these patients regarding the extent of the metastatic disease. MethodsPatients with extrathoracic metastatic NSCLC were identified in the US National Cancer Institute Surveillance, Epidemiology, and End Results database (2010–2015). Survival was compared before and after matching. Multivariate Cox regression models were built to identify factors associated with survival and to adjust for covariates in subgroup analysis. ResultsOf the 39,655 patients, 1206 underwent primary tumor resection, and 630 patients were identified 1:1 in surgical and nonsurgical groups after matching. In the entire cohort, patients who underwent surgery had significant prolonged overall survival (OS) in both unmatched (median survival time, [MST]: 14 vs. 6 months, p < 0.001) and matched (MST: 11 vs. 7 months, p < 0.001) cohorts. In the highly selected surgery-recommended cohort, surgical group still had a significantly longer OS (MST: 14 vs. 6 months, p < 0.001). Multivariate regression showed that surgery was independently associated with improved OS and lung cancer-specific mortality (LCSM) (OS: hazard ratio [HR]: 0.60, 95% confidence interval [CI]: 0.56-0.64, p < 0.001; LCSM: subhazard ratio [SHR]: 0.61, 95% CI: 0.57-0.66, p < 0.001). Subgroup analysis showed that surgery was an independent favorable predictor to survival in all cohorts except patients with N3 disease, and patients with single-organ metastasis were associated with the most prominent survival benefit from surgery. ConclusionsPrimary tumor resection was associated with improved survival in extrathoracic metastatic NSCLC patients, particularly for those with single-organ metastasis.