Prognostic Relevance of Tumour Size in T3a Renal Cell Carcinoma: A Multicentre Experience

Abstract Objective To evaluate the prognostic role of tumour size in pathological stage T3a renal cell carcinoma (RCC) with fat invasion only and to assess whether this subgroup maintains its relevance over the other pathological stages. Methods We retrospectively studied 2113 patients from eight international institutions who were treated by surgical resection for T2–4 RCC. Disease-specific survival (DSS) was evaluated with univariate and multivariate analyses. Results Univariate analysis of patients with T3a RCC showed that tumour size was significantly associated with DSS (HR: 1.09, 95% CI: 1.05–1.12, p < 0.001). An ideal cut-off of 7 cm for these patients was identified with a scatter plot of Martingale residuals and tumour size. The two T3a groups were distinctly different with respect to clinicopathologic parameters (performance status, metastases, grade, histological subtype) and survival ( p < 0.001). Median survival time was not reached for patients with T2 and T3a ≤ 7 cm disease with a 5- and 10-yr DSS rate of 70% and 59% and 63% and 53%, respectively. Median survival time for patients with T3a > 7 cm, T3b, T3c, and T4 disease was 54, 46, 21, and 11 mo, respectively, with 5- and 10-yr DSS rates of 46% and 36%, 46% and 36%, 34% and 0%, and 16% and 14%, respectively. Conclusions Our data indicate that tumour size is an important factor for predicting outcome of patients with T3a RCC with fat invasion only. Our findings should merit consideration during the next revision of the TNM classification.