Strength and weakness of the new TNM classification for lung cancer.

T he article by STRAND et al. [1] on the evaluation of the new tumour, node, metastasis (TNM) classification and staging system for lung cancer raises important questions on the validity of the classification and its therapeutic implications in clinical practice. The authors analysed a population-based series of 1,885 patients who underwent operation for lung cancer and who were registered at the Cancer Registry of Norway from 2001 to 2005. They pathologically classified these tumours according to the 6th [2] and 7th [3] editions of the TNM classification to assess their prognostic capacity, and found that the 7th edition did not improve the overall predictive ability of the staging system. Moreover, based on the current indications of therapy, nearly one-fifth of the patients could be offered different treatment options because of the rearrangement of some TNM subsets in different stages. Whether this different treatment will result in an improved prognosis is unknown.