[Impact of tumor diameter on prognosis in patients with renal cancer stage pT3a.].

Objective: To determine the prognostic impact that tumor size has in patients with pathological renal cancer stage pT3a.

Methods: Retrospective, descriptive study evaluating 261 patients diagnosed with renal cancer pathological stage pT1-3aN0M0 between 1995 and 2013. Clinical and pathological characteristics were evaluated in each group. A ROC curve was used to determine the optimum cutting point of tumor size in relation to the death by cancer. Metastasis-free survival and cancer specific survival were evaluated by the Kaplan Meier method and the differences between the groups were evaluated by the Log Rank test. Multivariate Cox regression analysis was used to evaluate the relationship of tumor size and survival of these patients.

Results: 261 patients were studied, 166 of which (63.6%) were Stage pT1a-b, 49 (18.8%) pT2 and 46 (17.6%) pT3a. Patients with pT3a tumors had higher proportion of symptomatic tumors (56.5% vs 33.6% p 0.003), tumor size (7.1 cm vs 5.5 cm; 0.0007), Fuhrman grade 3-4 (52.2% vs 19.1% p 0.0001), coagulative necrosis (62.8% vs 28.8% p 0.0001), distance metastasis (39.1% vs 14.9%; p 0.0001) and death by cancer (23.9% vs 8.9%; p 0.003) when compared with localized tumors (pT1-2). The ROC curve demonstrated that a cut-off point of 7cm is the ideal tumor size to determine renal cancer mortality. Metastasis-free survival at 5 year was 90% for tumors pT1a-b, 71% for pT2, 83% for pT3a <7cm and 48% for pT3a >7cm, with significant statistical differences (Log-rank test <0.001). In the multivariate analysis, only pT3a >7cm stage was an independent predictor of death by renal cancer.

Conclusions: Although perirenal fat invasion and renal vein invasion (pT3a stage) are accepted as prognostic factors, to differentiate this category by tumor size could improve its predictive quality. The tumor diameter (7cm) should be applied to pT3a tumors in order to improve the accuracy of TNM system.