Updated staging system for lung cancer.

The seventh edition of TNM for Lung Cancer came into effect on the first of January 2011. Containing more than 100,000 cases of lung cancer treated by all modalities of care and from around the world, this is the largest database ever accumulated for this purpose. This edition allows detailed analysis and intensive validation such that the resultant classification aligns stage with prognosis more closely than ever before. There have been changes to certain tumor and metastasis descriptors and the resultant stage groupings. This article describes these changes, provides more in-depth discussion of the changes, and provides much additional information.