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

Abstract

BackgroundOnly 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 methodsWe 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.ResultsLung cancer was newly diagnosed in 21 participants (2.3% per year). The percent-age 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.ConclusionThe 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.

The Incidence and Risk Analysis of Lung Cancer Development in Patients with Chronic Obstructive Pulmonary Disease: Possible Effectiveness of Annual CT-Screening

“…Several studies have shown that as the degree of emphysema becomes more severe, the incidence of lung cancer increases. 9,17,18 Our results are consistent with these reports.…”

“…In this study, we found 19 newly diagnosed cases of lung cancer in COPD patients during a median observation period of 4.58 years. The lung cancer incidence was 1.85%/year but has been reported to be 0.8% to 1.7%/year in COPD patients; 7 , 8 however, recent observational studies in Japan have reported that the incidence ranges from 2.06% to 2.30%/year, 9 , 10 which indicates that lung cancer incidence is continuing to increase. Our results are consistent with these reports.…”

“… 7 , 8 On the contrary, a three-year observational study in Japan recently reported that the incidence of lung cancer in COPD patients was 2.30%/year. 9 Similarly, according to an eight-year observational study conducted in Japan, Haruna et al reported that the incidence of lung cancer was 2.06%/year. 10 …”

“…10,16 The degree of emphysematous lesions has been reported to be associated with lung cancer development in COPD patients. 9,17,18 One study reported an increased risk of lung cancer as COPD airflow limitations progressed. 19 In contrast, a recent study stated that patients with milder stages of COPD are at higher risk for lung cancer than those with moderate or severe COPD.…”

<p>The Impact of Smoking on Pulmonary Metastasis in Colorectal Cancer</p>

“…Primary lung cancer is known to occur around emphysematous lesions, which suggests that a "field" that retains avascular and alveolar lesions is necessary as a cancer origin. 22 On the other hand, clinical studies have suggested that active smoking, rather than prior smoking likely causes pulmonary metastasis. The reason is that the number of cancer cells drained into the lung is critical and the avascular area due to emphysema does not favor pulmonary metastasis.…”