The current TNM staging system of renal cell carcinoma: are further improvements needed?

Objective of the study is to review the current 7th edition of the TNM classification of renal tumors and to perform a critical analysis of the recent evidence in order to identify the limitations of this new staging system. A search of the english literature was performed through the Medline and Pubmed database using the following keywords: renal cell carcinoma, staging system and TNM. Overall, 2600 references were initially scrutinized. Forty papers were selected based on their pertinence with the topic of the review, level of evidence provided and overall contribution to the field. Few changes have been made in the current version of the TNM staging system of renal tumors. pT2 tumors have been divided in 2 subgroups based on tumor size with a cut-off at 10 cm; the invasion of the renal vein was classified as pT3a; finally, the invasion of the ispsilateral adrenal gland was classified as pT4. However, other changes were suggested by the analysis of the recent literature and have not been introduced in this new version. Further improvements of the TNM classification for renal tumors are needed especially with regard to locally advanced tumors and node-positive disease, in order to improve the accuracy of this important prognostic tool in renal oncology.