Association between smoking status and brain metastasis intervals and the prognosis of brain metastasis in patients with non-small cell lung cancer

Abstract

Objective This study aimed to explore the association between smoking status and brain metastasis intervals in patients with non-small cell lung cancer (NSCLC), and its impact on the survival time of patients with brain metastasis. Methods Data were collected from patients with NSCLC with brain metastases who were treated at our centre between January 2005 and December 2017. Clinical indices such as clinicopathological features and smoking status were collected, and patients were followed up (cut-off: 1 September 2022). According to the inclusion and exclusion criteria, 461 patients were analysed and matched using 1:1 propensity score matching. Non-smokers (n = 113), smoking cessation (n = 113), and smokers (n = 113) formed balanced groups, and the duration of brain metastasis and overall survival were compared between groups. Results There was a statistically significant difference between the non-smoking and smoking cessation groups (P = 0.001), as well as between the non-smoking and smoking groups (P < 0.001). The time interval of brain metastasis between the smoking cessation and smoking groups was not significantly different (P = 0.106). Statistically significant factors in the multivariate and univariate analyses showed that smoking status, clinical stage, lung cancer operation, chemotherapy, and chest radiotherapy were independent predictors of the time interval of brain metastasis. Multivariate analysis showed that smoking status, driving gene mutations, and chest radiotherapy independently influenced survival after brain metastasis. Conclusion Smoking status in patients with NSCLC affected the interval of brain metastasis and survival after brain metastasis.