Lung cancer risk among patients with combined pulmonary fibrosis and emphysema.

Although combined pulmonary fibrosis and emphysema (CPFE) might be relevant to lung cancer, no comparison studies have been done. We evaluated the risk of lung cancer among CPFE patients compared to IPF and emphysema patients. We retrospectively reviewed the medical records of patients who were diagnosed as CPFE, IPF and emphysema using chest CT scans at Seoul National University Hospital from Jan 2000 to Dec 2011. Patients with CPFE were enrolled and matched (1:1:2) with IPF and emphysema patients based on the radiological criteria. The main outcome was time to diagnosis of lung cancer and evaluated with Cox-proportional hazard regression. Forty-eight CPFE, 48 IPF, and 96 emphysema patients were included in this study. Twenty-five cases of lung cancer occurred. The CPFE group had a higher risk of lung cancer (adjusted HR 4.62, 95% CI 1.58-13.55) than that of the emphysema group. Also, IPF group had a higher risk of lung cancer (adjusted HR 4.15, 95% CI 1.03-16.78) than that of emphysema group. However, there was no statistically significant difference in lung cancer risk between the CPFE and IPF group. Additionally, the CPFE group had a higher risk of lung cancer or death (adjusted HR 4.62, 95% CI 2.25-9.47) than that of the emphysema group. In conclusion, patients with CPFE and IPF had a higher risk of lung cancer than those with emphysema, although lung cancer risk was similar between CPFE and IPF.