Kattan postoperative nomogram for renal cell carcinoma: predictive accuracy in a Japanese population

The aim of the current study was to establish the predictive accuracy of the Kattan postoperative nomogram for non-metastatic renal cell carcinoma (RCC) in a Japanese population.

A total of 211 patients with stage T1-3N0M0 clear cell RCC who underwent radical nephrectomy or nephron-sparing surgery between 1991 and 2004 were included in this analysis. Median follow up was 81 months (range: 4-208). Univariate and multivariate analyses were performed, and the influence of age, sex, clinical presentation, T stage, histological tumor size, grade, and microvascular invasion on disease recurrence-free survival (RFS) was determined. For each patient, the prognostic score for 5-year RFS was calculated using the Kattan nomogram. The discriminating ability of this model was assessed by the concordance index, and bootstrapping was used to evaluate confidence intervals.

The 5-year RFS rate for all patients calculated using the Kaplan-Meier method was 80.6%. In multivariate analysis, the statistically significant prognostic factors for 5-year RFS were high-grade tumors (P=0.019) and symptomatic disease (P=0.017). The concordance index for RFS predicted by the Kattan nomogram was 0.735 (95% confidence interval: 0.734-0.736). There was a slight discrepancy between the RFS predicted by the Kattan nomogram and the likelihood of being recurrence-free at 5 years according to the Cox analysis in the current patient population.

These findings suggest the necessity of constructing a more useful nomogram for predicting the prognosis of Japanese patients with non-metastatic RCC.