Purpose: We determined whether renal vein ostium wall invasion could be predicted by renal vein and inferior vena cava diameter on imaging. We also determined whether it is a prognostic factor for recurrence and survival after radical nephrectomy and thrombus ablation for renal cell carcinoma with an inferior vena cava tumor thrombus.
Materials and methods: From January 2000 to January 2006 nephrectomy for renal cell carcinoma was performed in 446 patients, of whom 32 (7.2%) underwent inferior vena cava thrombus extraction with complete resection of the renal vein ostium. When necessary, inferior vena cava partial and circumferential ablation was done in 5 and 8 patients, respectively, as well as replacement for thrombus adhesions. The largest coronal or axial diameter of the renal vein ostium and inferior vena cava anteroposterior diameter were measured on preoperative magnetic resonance imaging. Renal vein ostium wall invasion was assessed in all patients and determined microscopically by tumor cell infiltration into the intima. ROC curves were used to assess the value of these measurements for diagnosing patients with renal vein ostium invasion with 90% sensitivity. The risk of recurrence and survival was analyzed.
Results: Renal vein ostium wall invasion was present in 13 of 32 patients (40.6%). It significantly correlated with mean +/- SD inferior vena cava anteroposterior diameter (27.8 +/- 10.2 vs 17.3 +/- 6.8 mm, p = 0.01) and with the largest mean renal vein ostium diameter (22.3 +/- 7.9 vs 12.6 +/- 6.9 mm, p = 0.01). The upper level of the inferior vena cava thrombus correlated with renal vein ostium invasion (p = 0.002). The inferior vena cava anteroposterior diameter or renal vein ostium diameter cutoff value to predict wall invasion with 90% sensitivity was 18 and 14 mm, respectively. The AUC was 0.78 for inferior vena cava diameter and 0.86 for renal vein ostium diameter. No inferior vena cava recurrence was observed. Renal vein ostium wall invasion was associated with a higher risk of recurrence and decreased specific survival (p = 0.01 and 0.03, respectively). The association of ostium renal vein wall invasion with death from renal cell carcinoma was seen on multivariate analysis after adjusting for tumor size, TNM stage and thrombus level (RR 5.9, 95% CI 1.45-30.8, p = 0.01).
Conclusions: Preoperative imaging measurements of renal vein and inferior vena cava diameter can accurately predict renal vein ostium wall invasion. Renal vein ostium wall invasion is an independent prognostic marker that is associated with a higher risk of recurrence and decreased specific survival.