Role of presurgical targeted molecular therapy in renal cell carcinoma with an inferior vena cava tumor thrombus

Purpose: The clinical benefit of targeted molecular therapy (TMT) in renal cell carcinoma (RCC) with an inferior vena cava (IVC) tumor thrombus remains controversial. The aim of this study was to investigate the effects of presurgical TMT on the heights and levels of IVC thrombi, and to assess its impact on surgical strategy. Patients and methods: We retrospectively reviewed data from 18 patients with RCC involving IVC tumor thrombi who were treated at our hospital with presurgical TMT followed by an IVC thrombectomy. The changes in heights and levels of the IVC thrombi were compared using computed tomography or magnetic resonance imaging. Clinicopathological factors were also evaluated to assess their association with TMT efficacy. Results: The tumor thrombus levels before TMT were stage I in 1 patient (5.6%), II in 12 patients (66.7%), III in 4 patients (22.2%), and IV in 1 patient (5.6%). After a median of two treatment cycles (range: 1-3), the thrombus height decreased measurably in 11 patients (61.1%) with an average shrinkage of 17.7%. The thrombus height remained stable in five patients (27.8%) and was enlarged in two (11.1%). Downstaging of the thrombus level occurred in four patients (22.2%); the surgical strategy was modified in three patients (16.7%) to avoid cardiopulmonary bypass and complicated liver mobilization under robot-assisted laparoscopy. Furthermore, a higher neutrophil count tended to be associated with a worse clinical TMT-associated outcome (P=0.056). Conclusion: Our data suggest a limited influence of presurgical TMT with a positive benefit in RCC patients with level III and IV thrombus. Thrombus-level regression may potentially alter the surgical strategy, especially robotic surgery. However, our findings require validation with additional prospective investigations.