Swensen, Stephen J.

Abstract The contribution of emphysema to lung cancer risk has been recognized, but the effect size needs to be further defined. In this study, 565 primary lung cancer cases were enrolled though a prospective lung cancer cohort at Mayo Clinic, and 450 controls were smokers participating in a lung cancer screening study in the same institution using spiral computed tomography (CT). Cases and controls were frequency matched on age, gender, race, smoking status, and residential region. CT imaging using standard protocol at the time of lung cancer diagnosis (case) or during the study (control) was assessed for emphysema by visual scoring CT analysis as a percentage of lung tissue destroyed. The clinical definition of emphysema was the diagnosis recorded in the medical documentation. Using multiple logistic regression models, emphysema (≥5% on CT) was found to be associated with a 3.8-fold increased lung cancer risk in Caucasians, with higher risk in subgroups of younger (<65 years old, OR = 4.64), heavy smokers (≥40 pack-years, OR = 4.46), and small-cell lung cancer (OR = 5.62). When using >0% or ≥10% emphysema on CT, lung cancer risk was 2.79-fold or 3.33-fold higher than controls. Compared with CT evaluation (using criterion ≥5%), the sensitivity, specificity, positive and negative predictive values, and the accuracy of the clinical diagnosis for emphysema in controls were 19%, 98%, 73%, 84%, and 83%, respectively. These results imply that an accurate evaluation of emphysema could help reliably identify individuals at greater risk of lung cancer among smokers. Cancer Prev Res; 4(1); 43–50. ©2010 AACR.

Purpose Low-dose computed tomography (CT) has been suggested for lung cancer screening. Several observational trials have published their preliminary results, and some investigators suggest that this technique will save lives. There are no mortality statistics, however, and the current study used published data from these trials to estimate the disease-specific mortality in this high-risk population. Patients and Methods Two nonrandomized CT screening trials were selected from the literature for analysis. The number of trial participants, the number of lung cancers diagnosed per year, and stage distribution of the cancers was recorded. Previously published 5-year survival data were used to calculate the number of predicted lung cancer deaths and estimate the overall lung cancer mortality per 1,000 person-years among participants screened. These statistics were then compared to the previous Mayo Lung Project, which used chest radiographs and sputum cytology for screening high-risk individuals. Results This study estimates the lung cancer mortality is 4.1 deaths per 1,000 person-years in the Mayo Clinic CT screening trial, and is 5.5 deaths per 1,000 person-years in the Early Lung Cancer Action Program trial. These data are similar to the lung cancer mortality of 4.4 deaths per 1,000 person-years in the interventional arm, and 3.9 deaths per 1,000 person-years in the usual-care arm of the previous Mayo Lung Project. Conclusion These data suggest that CT screening could produce similar outcomes to prior chest radiographic trials in this high-risk group. Results from randomized trials are required, however, before the true utility of mass screening with CT for lung cancer can be determined.

Abstract Bronchiolar abnormalities are relatively common and occur in a variety of clinical settings. Various histopathologic patterns of bronchiolar injury have been described and have led to confusing nomenclature with redundant and overlapping terms. Some histopathologic patterns of bronchiolar disease may be relatively unique to a specific clinical context but others are nonspecific with respect to either etiology or pathogenesis. Herein, we present a scheme separating (1) those disorders in which the bronchiolar disease is the predominant abnormality (primary bronchiolar disorders) from (2) parenchymal disorders with prominent bronchiolar involvement and (3) bronchiolar involvement in large airway diseases. Primary bronchiolar disorders include constrictive bronchiolitis (obliterative bronchiolitis, bronchiolitis obliterans), acute bronchiolitis, diffuse panbronchiolitis, respiratory bronchiolitis, mineral dust airway disease, follicular bronchiolitis, and a few other rare variants. Prominent bronchiolar involvement may be seen in several interstitial lung diseases, including hypersensitivity pneumonitis, respiratory bronchiolitis–associated interstitial lung disease, cryptogenic organizing pneumonia (idiopathic bronchiolitis obliterans organizing pneumonia), and pulmonary Langerhans' cell histiocytosis. Large airway diseases that commonly involve bronchioles include bronchiectasis, asthma, and chronic obstructive pulmonary disease. The clinical relevance of a bronchiolar lesion is best determined by identifying the underlying histopathologic pattern and assessing the correlative clinico–physiologic–radiologic context.