Radiologic features of precancerous areas of the lungs in chronic obstructive pulmonary disease

Abstract

Shotaro Chubachi,1 Saeko Takahashi,1 Akihiro Tsutsumi,1 Naofumi Kameyama,1 Mamoru Sasaki,1 Katsuhiko Naoki,1 Kenzo Soejima,1 Hidetoshi Nakamura,2 Koichiro Asano,3 Tomoko Betsuyaku1 On behalf of the Keio COPD Comorbidity Research Group 1Division of Pulmonary Medicine, Department of Medicine, Keio University School of Medicine, Shinjuku-ku, Tokyo, 2Department of Respiratory Medicine, Saitama Medical University, Irima-gun, Saitama, 3Division of Pulmonary Medicine, Department of Medicine, Tokai University School of Medicine, Isehara-shi, Kanagawa, Japan Background: Only a few studies have evaluated the radiologic features of pre-existing structural abnormalities where lung cancer may develop. This study aimed to analyze the computed tomography (CT) images of lung areas where new cancer developed in chronic obstructive pulmonary disease (COPD) patients. Patients and methods: We conducted a multicenter, longitudinal cohort study, called the Keio COPD Comorbidity Research, to assess the incidence of lung cancer. Emphysema and interstitial abnormalities were evaluated in 240 COPD patients who had baseline CT scans applicable for further digital analyses. For patients who developed lung cancer during the 3-year follow-up period, the local spherical lung density of the precancerous area was individually quantified. Results: Lung cancer was newly diagnosed in 21 participants (2.3% per year). The percentage of low attenuation area in patients who developed lung cancer was higher than that of the other patients (20.0% vs 10.4%, P=0.014). The presence of emphysema (odds ratio [OR] 4.2, 95% confidence interval [CI] 1.0–29.0, P=0.049) or interstitial lung abnormalities (OR 15.6, 95% CI 4.4–65.4, P<0.0001) independently increased the risk for lung cancer. Compared with the density of the entire lung, the local density of the precancerous area was almost the same in patients with heterogeneous emphysema, but it was higher in most patients with interstitial abnormalities. Conclusion: The presence of emphysema or interstitial abnormalities or a combination of both were independent predictors of lung cancer development in COPD patients. Furthermore, lung cancer most often developed in non-emphysematous areas or in interstitial abnormalities. Keywords: COPD, lung cancer, emphysema, interstitial lung disease, computed tomography

Keywords

• chronic obstructive pulmonary disease
• lung cancer
• emphysema
• interstitial lung disease
• computed tomography