Introduction: The 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.
Methods: All 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) 7 edition 2009 staging systems.
Results: We 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.
Conclusion: Although 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.