Smoking-related changes in the background lung of specimens resected for lung cancer: a semiquantitative study with correlation to postoperative course

To assess the pathological findings in lobectomy specimens, to correlate them with smoking history and postoperative course and to compare the findings with those in smoking-related interstitial lung disease. Patients who had undergone lobectomy for lung cancer were reviewed. Subjects included 230 non-smokers and 587 smokers, of whom 572 had a known smoking index (SI). They were classified into mild, moderate and heavy smokers. Centrilobular emphysema (CLE), respiratory bronchiolitis, airspace enlargement with fibrosis (AEF), the presence of foci resembling usual interstitial pneumonia pattern (UIP/P) and the rate of postoperative respiratory failure were assessed. The incidence of AEF was 6.5% in mild smokers, and 17.7% in moderate smokers (P < 0.01) with lower lobe predominance. There were significant correlations (P < 0.01) between AEF and CLE and AEF and UIP/P. The rate of respiratory failure after lobectomy was 6%, and 10% in patients having UIP/P with or without AEF, but was not seen in patients with AEF alone (P < 0.01). AEF is an important smoking-related change in the lung that appears to correlate with the smoking history, and its distinction from UIP/P may be important.