The Associations of Interstitial Lung Abnormalities with Cancer Diagnoses and Mortality

Abstract

An increased incidence of lung cancer is well-known among patients with idiopathic pulmonary fibrosis. It is unknown whether interstitial lung abnormalities, early fibrotic changes of the lung, are a risk factor for lung cancer in the general population.

The study's objective was to assess whether interstitial lung abnormalities were associated with diagnoses of, and mortality from, lung cancer and other cancers. Data from the AGES-Reykjavik study, a cohort of 5764 elderly Icelanders, were used. Outcome data were ascertained from electronic medical records. Gray's tests, Cox proportional hazards models and proportional subdistribution hazards models were used to analyse associations of interstitial lung abnormalities with lung cancer diagnoses and lung cancer mortality as well as diagnoses and mortality from all cancers.

Participants with interstitial lung abnormalities had greater cumulative incidence of lung cancer diagnoses (p<0.001) and lung cancer mortality (p<0.001) than others. Interstitial lung abnormalities were associated with an increased hazard of lung cancer diagnosis (HR=2.77) and lung cancer mortality (HR=2.89) in adjusted Cox models. Associations of interstitial lung abnormalities with all cancers were found in models including lung cancers but not in models excluding lung cancers.

People with interstitial lung abnormalities are at increased risk of lung cancer and lung cancer mortality, but not of other cancers. This implies that an association between fibrotic and neoplastic lung diseases of the lung exists from the early stages of lung fibrosis and suggests interstitial lung abnormalities as a risk factor in lung cancer screening efforts.