Advanced Renal Cell Carcinoma With Inferior Vena Cava Thrombus Treated With a Combination of Preoperative Lenvatinib and Pembrolizumab

Background/Aim: Lenvatinib plus pembrolizumab combination therapy is a safe and effective treatment for patients with advanced renal cell carcinoma (RCC). However, there are no reports of the use of lenvatinib and pembrolizumab combination therapy for RCC with an inferior vena cava (IVC) tumor thrombus. Herein, we describe a case in which pembrolizumab and lenvatinib combination therapy was effectively used to treat RCC with the IVC tumor thrombus extending to the right atrium. Case Report: A 73-year-old man was diagnosed with a right renal tumor with the IVC tumor thrombus extending to the right atrium and multiple pulmonary metastases (cT3cN0M1). Using a computed tomography-guided renal tumor biopsy, the tumor was diagnosed as clear cell RCC. The International Metastatic RCC Database Consortium risk classification was poor according to three risk factors, and lenvatinib and pembrolizumab combination therapy was initiated. The primary renal tumor shrunk, the IVC tumor thrombus that reached the right atrium was reduced from level 4 to level 2, and the lung metastases disappeared 4 months after treatment initiation. Thereafter, a robot-assisted deferred cytoreductive nephrectomy was successfully performed. Pathologically, owing to the preoperative combination therapy, most of the tumor tissue was necrotic; however, some viable cells were present in the primary tumor and IVC tumor thrombus. Eight months following the operation, the patient remains recurrence-free. Conclusion: Treatment with lenvatinib and pembrolizumab combination therapy led to tumor shrinkage and allowed robot-assisted nephrectomy in a patient with advanced RCC with the IVC tumor thrombus extending to the right atrium, corroborating the efficacy of the treatment.