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< or =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