Predominant histologic subtype in lung adenocarcinoma predicts benefit from adjuvant chemotherapy in completely resected patients: discovery of a holy grail?

The recently published 2015 World Health Organisation (WHO) classification of lung tumors, which is based on the 2011 International Association for the Study of Lung Cancer (IASLC)/American Thoracic Society (ATS)/European Respiratory Society (ATS) multidisciplinary classification, recommends diagnosis of resected lung adenocarcinoma according to the predominant histologic subtype. This has been shown to correlate with overall and disease-free survival (DFS) in many studies from four continents. Now classification according to predominant histologic subtype has been demonstrated to predict benefit from adjuvant chemotherapy in a subset of patients with completely resected lung adenocarcinoma previously included in the International Adjuvant Lung Cancer Trial (IALT), JBR.10, Cancer and Leukemia Group B (CALGB) 9633 and Adjuvant Navelbine International Trialist Association 01 (ANITA) adjuvant chemotherapy trials, all of which were part of the LACE-Bio study. This “hot-off-the press” landmark investigation further cements the clinical importance of classification of resected lung adenocarcinoma according to predominant histologic subtype and suggests that it could be a critical factor for patient stratification in future clinical trials.