Prognostic impacts of extracranial metastasis on non‐small cell lung cancer with brain metastasis: A retrospective study based on surveillance, epidemiology, and end results database

This study was designed to investigate the prognostic value of the number and sites of extracranial metastasis (ECM) in NSCLC patients with BM. NSCLC patients with BM from the Surveillance, Epidemiology, and End Results (SEER) database from 2010 to 2015 were enrolled in analysis. Patients from 2010 to 2013 were included in the training set and those from 2014 to 2015 in the validation set. ECM sites among different subtypes of NSCLC were compared by Chi‐square tests. Kaplan–Meier methods and Cox regression models were performed to analyze survival data. Competing‐risks analysis was used to predict cumulative incidence rates for CSS and non‐CSS cause. We included 5974 patients in the training cohort and 3561 patients in the validation cohort. Most (nearly 80%) NSCLC patients with BM showed 0–1 involved extracranial organ, with the most and least common ECM organ being bone and distant lymph nodes (DLNs) among all subtypes of NSCLC, respectively. The number of involved extracranial organs was an independent prognostic factor for patients with BM from NSCLC (p < 0.001). Patients with 0–1 ECM had better survival than those with larger number of involved extracranial organs (p < 0.001). Cumulative incidence rates for CSS were increased with the number of ECM raising (p < 0.001). All involved extracranial organs were associated with worse survival (p < 0.05). In patients with single‐organ ECM, we observed a better prognosis in lung and bone metastasis, while liver metastasis showed worst survival. But the difference in survival in these patient groups was relatively small. Patients with liver metastasis had higher cumulative incidence rates for CSS than that in patients with lung and bone metastasis (p < 0.05). More extracranial metastases were associated with poor prognosis in NSCLC patients with BM and ECM sites showed limited effect on survival. Tailored treatments would be reasonable for BM patients from NSCLC with different metastasis patterns.