The detection, assessment and clinical evolution of interstitial lung abnormalities identified through lung cancer screening.

Introduction: Interstitial lung abnormalities (ILAs) are common incidental findings in lung cancer screening; however, their clinical evolution and longer-term outcomes are less clear. The aim of this cohort study was to report 5-year outcomes of individuals with ILAs identified through a lung cancer screening programme. In addition, we compared patient-reported outcome measures (PROMs) in patients with screen-detected ILAs to newly diagnosed interstitial lung disease (ILD) to assess symptoms and health-related quality of life (HRQoL). Methods: Individuals with screen-detected ILAs were identified, and 5-year outcomes, including ILD diagnoses, progression-free survival and mortality, were recorded. Risk factors associated with ILD diagnosis were assessed using logistic regression and survival using Cox proportional hazard analysis. PROMs were compared between a subset of patients with ILAs and a group of ILD patients. Results: 1384 individuals underwent baseline low-dose computed tomography screening, with 54 (3.9%) identified as having ILAs. 22 (40.7%) were subsequently diagnosed with ILD. 14 (25.9%) individuals died, and 28 (53.8%) suffered disease progression within 5 years. Fibrotic ILA was an independent risk factor for ILD diagnosis, mortality and reduced progression-free survival. Patients with ILAs had lower symptom burden and better HRQoL in comparison to the ILD group. Breathlessness visual analogue scale (VAS) score was associated with mortality on multivariate analysis. Conclusions: Fibrotic ILA was a significant risk factor for adverse outcomes including subsequent ILD diagnosis. While screen-detected ILA patients were less symptomatic, breathlessness VAS score was associated with adverse outcomes. These results could inform risk stratification in ILA.