Abstract
PURPOSE: In this nationwide 5-year longitudinal population-based study, we aimed at investigating the incidence of lung cancer among patients with interstitial lung disease. MATERIALS AND METHODS: Data was collected from the Korean National Health Insurance Research Database from 49,773,195 Korean residents in 2009. Thirteen thousand six hundred and sixty-six patients with interstitial lung disease diagnosed January-December 2009. The end of follow-up was June 30, 2014. Up to four matching chronic obstructive pulmonary disease controls were selected to compare the lung cancer high-risk group based on age, sex, diagnosis date (within 30 days), and hospital size. The number of patients with newly developed lung cancer was determined. RESULTS: The incidences of lung cancer were 126.98, 156.62, and 370.38 cases per 10,000 person-years (2,732, 809, and 967 cases of cancer, respectively) in the chronic obstructive pulmonary disease, interstitial lung disease, and chronic obstructive pulmonary disease with interstitial lung disease groups, respectively. Of the 879 patients with idiopathic pulmonary fibrosis, 112 developed lung cancer (incidence, 381.00 cases per 10,000 person-years). CONCLUSION: Incidence of lung cancer among patients with interstitial lung disease was high. Interstitial lung diseases have a high potential for developing into lung cancer, even when concurrent with chronic obstructive pulmonary disease.