The International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society grading system has limited prognostic significance in advanced resected pulmonary adenocarcinoma

SummaryIntroductionThe International Association for the Study of Lung Cancer, the American Thoracic Society and the European Respiratory Society (IASLC/ATS/ERS) system which subclassifies lung adenocarcinoma into five distinct types has been widely adopted. We assessed the prognostic value of subclassifying adenocarcinoma in this way in consecutive patients undergoing surgery.MethodsAll patients at our institution undergoing surgery for lung carcinoma between 2000 and 2010 were identified. The original pathology slides were independently reviewed and reclassified according to the 2011 IASLC/ATS/ERS grading and the American Joint Committee on Cancer (AJCC) 7th edition 2009 staging systems.ResultsWe identified 270 patients including 152 with adenocarcinoma histology with long-term follow-up. Using the Kaplan-Meier method, the calculated 5 year survival for each of the adenocarcinoma categories were papillary-predominant 80%, lepidic-predominant 71%, micropapillary-predominant 55%, acinar-predominant 43%, solid-predominant 39% and invasive mucinous adenocarcinoma 38%. The AJCC stage was a very strong predictor of survival (p < 0.001). The IASLC/ATS/ERS subclassification of adenocarcinoma demonstrated a trend as a prognostic marker but failed to reach statistical significance in univariate or multivariate analysis.ConclusionAlthough the IASLC/ATS/ERS classification has been validated by several studies in stage I tumours, further studies of larger cohorts will be required to show prognostic value in unselected lung carcinoma undergoing surgery with curative intent.