Prognostic significance of the TNM classification of renal cell carcinoma:A comparison of the 4(th) and 5(th) editions

Introduction: In 1997, the 5(th) edition of the TNM classification of malig nancies was published. The most significant change from the 4(th) edition w as made in the T-stage. We compared both TNM staging classifications in ter ms of accuracy in predicting patient outcome. Materials and Methods: From 1975 to 1997, a total of 2014 patients underwen t surgical treatment for renal cell carcinoma at our hospital. The data of 1794 patients could be used in this retrospective analysis. Kaplan-Meier su rvival curves were generated and compared. Results: With regard to the prediction of patient outcome, the 5(th) editio n of the TNM staging classification - with a tumor size "cut off" of 7.0 cm between stages T1 and T2 - shows a significantly higher survival rate for stage T1 patients than the previous edition ("cut off" 2.5 cm). In addition , the same prognostic accuracy as the 5(th) edition was achieved with a "cu t off" of 4 cm. Conclusion: The 5(th) edition of the TNM classification shows a significant advantage in prognosis over the 4 th edition. An alternative classificatio n (T1 <4 cm, T2 greater than or equal to 4 cm), however, may furthermore im prove clinical usefulness in decision-making for organsparing surgery in el ective indications. In this instance, stage T1 patients could be selected f or partial nephrectomy, while stage T2 patients could not. Such an alternat ive classification permits better patient selection and is thus clinically more useful than the current TNM staging classification.