Prognostic significance of tumour size in patients after tumour nephrectomy for localised renal cell carcinoma

OBJECTIVES: Staging of the primary tumour is accepted as the most important prognostic factor in organ confined renal cell carcinoma. METHODS: The outcome of 286 patients with non-metastatic RCC treated by radical nephrectomy at our institution between 1968 and 1992 was evaluated retrospectively. The median follow-up was 114 +/- 62.6 months. In T1/T2 tumours, the validity of tumour size cut-off points for predicting survival outcome was tested. RESULTS: According to the 1997 TNM classification, 168 patients (59%) showed pathological stage T1 (72 stage T1a, 96 stage T1b), 30 (10%) showed stage T2, 84 patients (29%) demonstrated T3 tumours (53 stage T3a, 31 stage T3b), and 4 patients (2%) presented with T4 tumours. The median survival estimated by Kaplan-Meier analysis for T1a, T1b, T2, T3a, T3b and T4 tumours was over 300 months, 187.0 +/- 32.76; 177.0 +/- 1.21; 121.0 +/- 2.57; 124.0 +/- 11.82 and 52.0 +/- 18.38 months, respectively. Regarding survival in T1/T2 tumours Cox regression analysis yielded the highest significance level for a tumour size cut-off point at 4 cm (p = 0.003; 95%CI 1.511-6.991), but no prognostic value for a cut-off point at 7 cm (T1 vs. T2) (p = 0.375; 95%CI 0.655-3.071). CONCLUSIONS: Tumour size is an important prognostic factor in patients with organ confined RCC. The recently specified new cut-off point of 4 cm for T1a/T1b tumours is feasible for separating groups with different survival after tumour nephrectomy and should be considered as the new boundary between T1 and T2 stages. Hence, a more accurate prediction of prognostic differences between these groups should be possible.