Point-of-Care Spirometry Identifies High-Risk Individuals Excluded from Lung Cancer Screening

Respiratory Function as a Prognostic Factor for Lung Cancer in Screening and General Populations

Rationale: Despite advancements in screening, lung cancer remains the leading cause of cancer-related mortality globally. Objectives: To investigate respiratory function as a prognostic factor for survival in the UK Biobank, a population-based cohort of more than 500,000 participants, and the NLST (National Lung Screening Trial), a high-risk screening population of more than 50,000 screenees. Methods: Participants with an incident lung cancer diagnosis and spirometry-assessed lung function were included. Lung cancer was measured as the ratio of forced expiratory volume in 1 second (FEV1) and forced vital capacity and percentage of predicted FEV1. Multivariable Cox proportional hazards models were fitted to estimate the impact of lung function on 5-year overall survival in populations with different baseline lung cancer risks. Results: A total of 2,690 and 609 patients were included in the analysis from the UK Biobank and the NLST, respectively. In the UK Biobank, a higher percentage of predicted FEV1 and ratio were associated with better survival after lung cancer diagnosis, with hazard ratios of 0.97 (95% confidence interval [CI], 0.95-1.00 per 10% increase) and 0.95 (95% CI, 0.90-1.00 per 10% increase), respectively. No statistically significant results were found when assessing the data from the NLST study. Conclusions: Impaired lung function was associated with poorer survival for patients with lung cancer in the general population, although this was less clear in a high-risk, screening-eligible population. This highlights the potential clinical importance of respiratory function as a prognostic factor in lung cancer in the general population and presents a possibility for personalized cancer management.

Stratification and management of patients ineligible for lung cancer screening

This study identifies participants ineligible for lung cancer screening with the greatest likelihood of future eligibility. Lung cancer risk in participants enrolled in longitudinal lung screening was assessed using the Prostate, Lung, Colorectal and Ovarian lung cancer risk calculator (PLCO_m2012) at two timepoints: baseline (T₁) and follow-up (T₂). Separate analyses were performed on four PLCO_m2012 eligibility thresholds (3.25%, 2.00%, 1.50%, and 1.00%); only participants with a T₁ risk less than the threshold were included in that analysis. Cox-models identified T₁ risk factors associated with screen-eligibility at T₂. Three models, applying differing assumptions of participant behavior, predicted future eligibility and were benchmarked against the observed cohort. Nine hundred and fifty-six participants had a T₁ risk <3.25%; at 2.00% n= 755; at 1.50% n= 652; at 1.00% n= 484. Lung cancer risk increased over time in most screen-ineligible participants. However, risk increased much faster in participants who became screen-eligible at T₂ compared to those who remained screen-ineligible (median per-year increase of 0.35% versus 0.02%, when using a 3.25% threshold). Participants smoking for >30 years, current smokers, less educated participants, and those with chronic obstructive pulmonary disease (COPD) at T₁ were significantly more likely to become screen-eligible. New diagnoses of COPD and/or non-lung cancers between T₁ and T₂ precipitated eligibility in a subset of participants. The prediction model that assumed health behaviors observed at T₁ continued to T₂ reasonably predicted changes in lung cancer risk. This prediction model and the identified baseline risk factors can identify screen-ineligible participants who should be closely followed for future eligibility.