Prognostic factors for survival in a Chinese population presenting with advanced non-small cell lung cancer with an emphasis on smoking status: A regional, single-institution, retrospective analysis of 4552 patients

Background: Lung cancer ranks as the top of cancer-related mortality in the world. Approximately 8590% of all lung cancer cases are non-small cell lung cancer (NSCLC). For advanced NSCLC patients, the five-year survival rate is less than 5%. Previous studies have attempted to determine prognostic factors, such as smoking status, gender, ethnicity, age, and histological type. However, the results are controversial and conflict. In this study, we investigated prognostic factors in a Chinese population presenting with advanced NSCLC. Methods: Medical records of patients with advanced NSCLC (AJCC Stage IIIB/IV) who received treatment at our institution were reviewed. Kaplan-Meier method and Cox Proportional Hazards model were performed in both univariate and multivariate analyses. Results: A total of 4552 patients were entered. Among them, 1320 (29.0%) were female, 2408 non-smokers (52.9%), and all had Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) = 0/1. Univariate analysis suggested that female gender (P < 0.001), adenocarcinoma histology (P < 0.001), age <70 (P < 0.001), and non-smoker status (P < 0.001) were associated with better survival. However, multivariate analysis demonstrated that age (hazard ratio [HR]= 1.173, 95% confidence interval [CI]: 1.0851.268, P < 0.001), smoking status (vs. non-smokers, HR = 1.212, 95% CI: 1.1231.308, P < 0.001), and histological type (non-adenocarcinoma vs. adenocarcinoma, HR = 1.104, 95% CI: 1.0311.181, P = 0.004), but not gender, were independent prognostic factors. Conclusions: Smoking status, age, and histological type are independent prognostic factors in Chinese NSCLC patients presenting with advanced disease. Non-smoking status is associated with better overall survival in Chinese NSCLC patients.