Clinical characteristics and survival in non-small cell lung cancer patients by smoking history: a population-based cohort study

Acta Oncol. 2019 Nov;58(11):1618-1627. doi: 10.1080/0284186X.2019.1638521. Epub 2019 Aug 2.

Abstract

Introduction: Approximately, 10-15% of lung cancer patients have never smoked. Previous epidemiological studies on non-tobacco associated lung cancer have been hampered by selected data from a small number of hospitals or limited numbers of patients. By use of data from large population-based registers with national coverage, this study aims to compare characteristics and survival of patients with non-small cell lung cancer (NSCLC) with different smoking histories.Methods: Swedish national population-based registers were used to retrieve data on patients diagnosed with primary NSCLC between 2002 and 2016. The Kaplan-Meier method and Cox proportional hazard models were used to estimate overall survival and lung cancer-specific survival by smoking history.Results: In total, 41,262 patients with NSCLC were included. Of those, 4624 (11%) had never smoked. Never-smokers were more often women and older compared to ever smokers (current and former). Adenocarcinoma was proportionally more common in never-smokers (77%) compared to current (52%) and former smokers (57%). Stage IV disease was more common in never-smokers (57%) than in current (48%) and former smokers (48%). Epidermal growth factor receptor mutation was observed more in never-smokers (37%) compared to current (5%) and former smokers (9%). Both lung cancer-specific and overall survival were higher for never-smokers compared to current smokers.Conclusions: The observed differences in characteristics between never-smokers and smokers, and the higher survival in never-smokers compared to smokers from this large population-based study provide further evidence that lung cancer in never-smokers is clinically different to tobacco-associated lung cancer. The findings from this study emphasise the need for an improved understanding of genetics, pathogenesis, mechanisms and progression of non-tobacco associated lung cancer that may help prevent lung cancer or identify individually targeted treatments.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Carcinoma, Non-Small-Cell Lung / mortality*
  • Carcinoma, Non-Small-Cell Lung / pathology*
  • Carcinoma, Non-Small-Cell Lung / physiopathology
  • Cohort Studies
  • Female
  • Humans
  • Kaplan-Meier Estimate
  • Lung Neoplasms / mortality*
  • Lung Neoplasms / pathology*
  • Lung Neoplasms / physiopathology
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Proportional Hazards Models
  • Registries
  • Survival Rate
  • Sweden / epidemiology
  • Tobacco Smoking / adverse effects*