Prognostic significance of the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification of stage I lung adenocarcinoma: A retrospective study based on analysis of 110 Chinese patients

BACKGROUND: The aim of this study was to investigate the relationship between predominant subtype, classification, and prognosis in Chinese stage I lung adenocarcinoma patients according to the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society (IASLC/ATS/ERS) International Multidisciplinary Lung Adenocarcinoma Classification. METHODS: Between 2000 and 2010, 110 patients with stage I lung adenocarcinoma underwent surgery at Xuanwu Hospital. Two pathologists independently reclassified all resected specimens according to the IASLC/ATS/ERS classification. Survival curves were plotted using the Kaplan-Meier method. The Cox proportional hazard model was used for multivariate analysis. RESULTS: There were no cases of adenocarcinoma in situ, and three cases of minimally invasive adenocarcinoma. There were 107 cases of invasive adenocarcinoma: 12 lepidic, 32 acinar, 30 papillary, 18 micropapillary, and 15 solid predominant subtypes. Patients with micropapillary and solid predominant tumors had significantly poorer disease-free survival compared to those with other subtypes of predominant tumors (P = 0.021). Multivariate analysis revealed that the new classification (P = 0.003) and T stage (P = 0.034) were independent predictors of disease-free and overall survival, respectively. CONCLUSION: The predominant subtype in the primary tumor was associated with prognosis in resected stage I lung adenocarcinoma.