Clinical features of lung cancer in smokers with light and mild chronic obstructive pulmonary disease: a retrospective analysis of Japanese surgical cases

OBJECTIVES: We estimated the influence of chronic obstructive pulmonary disease (COPD) upon the clinicopathological characteristics of lung cancer (LC) in Japanese surgical cases by comparing LC cases in non-COPD smokers. METHOD: A consecutive cohort comprising 157 COPD patients (78 in Global Initiative for Obstructive Lung Disease-1 (GOLD-1) and 79 in GOLD-2) and 374 non-COPD smoker-LC patients were enrolled in this study. Comparative analyses of the clinicopathological features of these two groups, including clinical outcomes, were performed. RESULTS: By analyzing all cases, we found that LC patients with COPD were older on average, more likely to be male, and heavier smokers than LC patients without COPD. In sub-analysis involving matched patient backgrounds, histological differentiation grade of LC in smokers with COPD was lower than in LC smokers without COPD, although distribution of clinical stages and histological types of LCs did not differ between smokers with and without COPD. The 5-year-survival rate in COPD patients was poorer than in non-COPD smokers in terms of both overall (38% vs 54%) and cancer-related mortality (45% vs 63%). By single-variant risk analysis, COPD became a prognostic factor. CONCLUSION: We concluded from our analysis that COPD-related LC may have a higher malignant potential than LC in non-COPD smokers, as the histological differentiation grade and clinical outcomes were poorer.