Beginning with the 2002 AJCC staging system, renal sinus muscular venous branch invasion has prognostic equivalence with renal vein invasion (RVI) in renal cell carcinoma. To validate this presumed equivalence, we compared patients with isolated MVBI to those with RVI and to those without any confirmed vascular invasion.
From routine cataloging at Memorial Sloan-Kettering Cancer Center, we identified 500 patients who underwent partial or radical nephrectomy from 2003 to 2008. After excluding patients with metastasis or non-cortical RCC pathology, 85 patients with MVBI (+) were identified. Patients with pT1-2 MVBI (−) (n = 259) or RVI (+) (n = 71) disease served as comparison groups. A multivariable Cox model was used to control for tumor characteristics, using the Kattan RCC nomogram.
In multivariable analysis, the risk of recurrence in the pT1-2 MVBI (−) group was lower than in the MVBI (+) group (HR 0.06, 95% CI 0.02–0.18; p <0.001). Patients with RVI (+) had similar recurrence rates to those with MVBI (+) (HR 0.80, 95% CI 0.39–1.65; p = 0.6). Overall survival rates were higher in the MVBI (−) group than in the other groups.
Patients with MVBI have inferior outcomes compared to those with pT1-2 disease. This confirms the adverse prognosis of MVBI and supports pathologic upstaging. The prognosis of MVBI is similar to that of RVI, although we can’t exclude the possibility of a difference. Our findings underscore the importance of close patient follow-up and careful pathologic assessment of the nephrectomy specimen.