Implications of New (Seventh) TNM Classification of Lung Cancer on General Radiologists—A Pictorial Review

Authors: Vimal Raj, MBBS, FRCRCorresponding Author Informationemail address, Amrita Bajaj, DMRD, MD, FRCR, MRCP, James J. Entwisle, MBBCh, MRCP, FRCR

Lung cancer is the most common cancer worldwide, accounting for 1.2 million new cases annually and responsible for 17.8% of all cancer deaths.1 It has one of the lowest survival outcomes with a significant number of patients diagnosed at a late stage. Although early diagnosis would improve survival, patients tend to have significant associated comorbidity related to smoking and may not be fit for radical treatment.

The seventh edition of TNM (TNM-7) classification of lung cancer has been published by the Union Internationale Centre le Cancer and has been in use since January 2010.2 As part of the multidisciplinary team (MDT), radiologists play a key role in not only recognition and staging lung cancer but also its histologic diagnosis and follow-up. Therefore, it is essential that both general and thoracic subspecialty radiologists educate themselves and other members of the team about the proposed changes. This pictorial essay highlights the important changes between the sixth and seventh edition of the staging system and outlines its limitations and implications for radiologists.