Spirometry at diagnosis and overall survival in non-small cell lung cancer patients

Abstract

Pulmonary function can predict all-cause mortality, and chronic obstructive pulmonary disease (COPD) is associated with worse overall survival (OS) in non-small cell lung cancer (NSCLC) patients. Though pre-operative lung function is predictive of in-hospital mortality following lung cancer surgery, its predictive utility for long-term survival is unclear. The prognostic role of commonly used spirometry tests in survival of lung cancer also remains uncertain. This study evaluates the role of spirometry at lung cancer diagnosis in predicting OS of NSCLC patients. This was a retrospective study using data from the Boston Lung Cancer Study on newly diagnosed NSCLC patients with spirometry tests performed before cancer therapy (n = 2805). Spirometric test values, after being categorized using quartiles, were analyzed for association with OS using univariate and risk-adjusted multiple regression models. Further, we analyzed OS by the status of COPD determined by spirometry, and, among those with COPD, by its stage defined by the Global Initiative for Chronic Obstructive Lung Disease criteria. Both univariate and multiple regression models demonstrated that lower quartiles of actual and percent predicted forced expiratory volume in 1 second and forced vital capacity at lung cancer diagnosis were significantly associated with worse OS. Spirometry-determined COPD, and more advanced stage of COPD at lung cancer diagnosis were associated with worse lung cancer OS. The findings provide evidence that a good pulmonary function at diagnosis may help improve OS in NSCLC patients.

Keywords: epidemiology; lung cancer; prognostic factor; survival.

FIGURE 1

Inclusion for the study population and analytical cohort

FIGURE 2

HRs of OS for each spirometry test in univariate (N = 2805) and stratified multiple regression models (complete‐case analyses, N = 1958). Variables adjusted in the multiple regression models are age, sex, BMI, smoking status (previous smoker, or current smoker vs. never smoker), pack‐years, cancer stage (II, III, or IV vs. I), treatments (surgery + chemo/radiation, or chemo/radiation vs. surgery only), and time interaction terms with age, stage, and treatment; the multiple regression model was further stratified on NSCLC histological subtypes. Abbreviations: HR: hazard ratio; CI: confidence interval; FEV₁: forced expiratory volume in 1 second; FEV₁%: percent predicted FEV₁; FVC: forced vital capacity; FVC %: percent predicted FVC

FIGURE 3

Kaplan–Meier curve of OS by COPD stage (N = 2805). Advanced stages of COPD were associated with significantly shorter OS in lung cancer patients. Abbreviations: GOLD: Global Initiative for Chronic Obstructive Lung Disease