Risk Factors, Prognosis and A New Nomogram for Predicting Cancer-Specific Survival Among Lung Cancer Patients with Brain Metastasis: A Retrospective Study Based on SEER

Purpose: A comprehensive population-based study on risk and prognostic factors of lung cancer with brain metastasis is lacking. Methods: 95191 patients diagnosed with lung cancer between 2010 and 2017 were collected from the Surveillance, Epidemiology and End Results (SEER) database. Patients were stratified by different variables. Multivariable logistic and Cox regression were applied to analyze the risk and prognostic factors of brain metastasis among lung cancer patients, respectively. The Fine and Gray’s competing risk regression model was performed to obtain prognostic factors associated with cancer-specific mortality.Results: Among the 95191 patients diagnosed with lung cancer, 10765 patients have brain metastasis, with a metastatic incidence of 11.31%. The primary site of tumor, residence type, age, histological type, race and extracranial metastasis were all independent risk factors of brain metastasis. Compared with other histological types, small cell lung cancer displayed a highest incidence of brain metastasis (16.62%). The median overall survival (OS) among lung cancer patients with brain metastasis was only 6.05 months. The primary site of tumor, median household income, age, histological type, race, gender and extracranial metastasis were all associated with the prognosis of brain metastasis. Patients with squamous cell carcinoma had the worst prognosis, the median OS was only 3.68 months. And our established new nomogram showed a good discriminative ability on predicting the probability of cancer-specific survival among patients with brain metastasis, the C-index was 0.61.Conclusion: Our study provided a deeper insight into the risk factors and prognosis of brain metastasis among lung cancer patients.