Differential Prognostic Value of Extrarenal Involvement in Patients With Non-Metastatic Renal Cell Cancer

Introduction: A better definition of the prognostic significance of non-metastatic pT3a stage RCC subcategories is crucial to select the best candidate for adjuvant treatment. The aim of the study is to investigate the differential prognosis of extrarenal involvement in patients with non-metastatic pT3a RCC. Materialsand methods: From a single institutional prospective database, 451 consecutive patients treated for pT3aN0/NxM0 RCC were selected and stratified according to pT3a subtypes (perirenal fat invasion, sinus fat invasion, segmental/renal vein thrombus, ≥ 2 features). Cancer specific survival (CSS), metastasis free survival (MFS) and relapse free survival (RFS) were primary endpoints of multivariable Cox regression models. Results: Overall, 67 (15%) patients presented with renal/segmental vein thrombus only, 185 (41%) with perirenal fat invasion, 101 (22%) with sinus fat invasion and 98 (22%) with ≥ 2 features. The presence of ≥ 2 pT3a features was associated with a higher risk of metastasis (HR=2.36; 95%CI 1.30-4.27; P value = .005), recurrence (HR=2.41; 95%CI 1.36-4.28; P value=.003) and cancer specific mortality (HR=3.54; 95%CI 1.45-8.63; P value = .005) compared to only 1 pT3a feature. Moreover, the presence of perirenal fat invasion was associated with lower CSS (HR=2.82; 95% CI 1.19-6.69; P value = .02) compared to sinus fat invasion or tumoral thrombus only. Conclusion: The concurrent presence of ≥ 2 pT3a features is associated to a higher risk of distant progression, relapse and cancer specific mortality, implying potential role for adjuvant therapy or a more stringent follow-up. Moreover, perirenal fat invasion is associated with worse CSS compared to other pT3a patterns taken alone.