Abstract
Introduction: Interstitial lung disease (ILD) patients often develop lung cancer (LC). However, previous studies on the incidences of LC in ILDs focused on specific aetiologies, such as idiopathic pulmonary fibrosis (IPF). To investigate the incidences of LC in ILDs other than IPF, we conducted this study. Materials and Methods: ILD patients at our hospital were retrospectively reviewed. The cumulative incidences of LC in various ILD patients were estimated and compared among ILD groups for up to five years. The association between several variables at initial diagnosis and LC development was assessed to identify predictors. Results: In all, 587 ILD patients, including 161 IPF, 160 chronic HP, 133 non-IPF idiopathic interstitial pneumonias (IIPs), 87 connective tissue disease-related ILDs (CTD-ILDs), and 46 other ILDs, were included. Twenty-seven patients developed LC. The cumulative incidences of LC at 1, 3, and 5 years were 1.9%, 5.7%, and 12.3% in IPF, respectively; 2.0%, 4.6%, and 11.0% in chronic HP; 0.8%, 0.8%, and 4.0% in non-IPF IIPs; and 1.1%, 1.1%, and 2.9% in CTD-ILDs. Chronic HP patients had a high incidence of LC as IPF patients. Pack-years was associated with LC development in chronic HP patients. Conclusions: The incidences of LC are equally high in patients with chronic HP and IPF.
