Pathologic staging of renal cell carcinoma - Significance of tumor classification with the 1997 TNM staging system

BACKGROUND. The TNM staging system for renal cell carcinoma was revised by the American Joint Committee on Cancer (AJCC) and the International Union A gainst Cancer (UICC) in 1997. The 1997 TNM? staging system for renal cell c arcinoma reclassifies tumors using criteria for size and for extent of rena l vein/vena cava involvement that are different from the criteria used in t he 1987 staging system. The current study investigated the prognostic signi ficance of tumor classification and other factors using the new staging sys tem. METHODS, Records from 1547 renal cell carcinoma patients (1039 males and 50 8 females: mean age, 63.4 years; mean follow-up, 7.1 years) who underwent s urgical resection between 1970 and 1998 were analyzed retrospectively. Tumo rs were staged using the 1987 and 1997 TNM criteria, and Kaplan-Meier Estim ates of survival and disease recurrence were compared for both staging syst ems. The Peto-Peto log rank test and the generalized Wilcoxon test were use d to assess univariate significance of prognostic factors on survival. Cox proportional hazards regression analysis was then completed to assess the s ignificance of the revised staging system. RESULTS, Tumor classification using the 1987 TNM staging system (P = 0.0001 ) and the 1997 TNM staging system (P = 0.0001) was a significant predictor of cause specific survival. Using 1997 TNM staging criteria, 641 patients w ere reclassified from the T2 classification to the T1 classification, 114 p atients were reclassified from the T3c classification to the T3b classifica tion, 11 patients were reclassified from the T4b classification to the T3c classification, and 3 patients were reclassified from the T4b classificatio n to the T3b classification. Patients with reclassified rumors had outcomes similar to patients with tumors that remained in the same tumor classifica tion. Patient stratification was improved using the new staging system. Pro gnostic discrimination for cause specific survival at 10 years was noted fo r the 1987 and 1997 TNM classifications (T1, 97% vs. 91%; T2, 84% vs.:OW; T 3a, 53% vs. 53%; T3b, 48% vs. 42%; and T3c, 29% vs. 43%). CONCLUSIONS, The revised classification of renal cell carcinoma was a signi ficant predictor of cause specific survival for the cohort of patients desc ribed in this report. Using the new system, the stratification of patients was improved. Patients who had their tumors reclassified as a result of the new staging system had outcomes similar to those of patients who had tumor s that remained in the same classification. Based on an analysis of this co hort, turner classification is valid, and the T1 subclassification is warra nted. However, additional revision may be required to optimize staging. (C) 2001 American Cancer Society.