Evaluation of the 1997 tumour, nodes and metastases classification of renal cell carcinoma: experience in 172 patients

Objective To compare the prognostic relevance of the 1987 and 1997 tumour, nodes and metastases (TNM) systems for staging renal cell carcinoma (RCC) in predicting patient outcome. Patients and methods A series of 172 consecutive patients with RCC who underwent radical nephrectomy from January 1990 to October 1997 was evaluated comparatively according to the 1987 and 1997 TNM classifications. The median (range) follow‐up of the patients was 50 (19–112) months. The probability of survival was estimated by the Kaplan–Meier method, using the log‐rank test to estimate differences among levels of the analysed variables. Results Using the 1997 TNM classification resulted in a redistribution of 99 patients from stage pT2 on the 1987 TNM classification to stage pT1. As the staging criteria for pT3 and pT4 did not change, there was no re‐classification of these patients. Kaplan–Meier survival curves showed a similar separation in 5‐year survival between stage pT1 and pT2 using both systems; 100% vs 80% for the 1987 TNM and 86% vs 69% for the 1997 TNM systems. This difference in survival rates between patients with pT1 and pT2 disease was statistically significant only for the 1997 TNM staging system. However, when the 1987 TNM staging classification was applied, the separation in 5‐year survival rates between pT2 and pT3 disease was greater. Conclusion This study confirms the prognostic relevance of the 1987 TNM system, as established in the present patients. The 1997 TNM classification resulted in a better stratification of patients with pT1–pT2 disease, but had similar prognostic value for pT2 and pT3 disease.