A Case of Renal Cell Carcinoma With Inferior Vena Cava Tumor Thrombus Achieving Pathologic Complete Response Following Combination Therapy With Lenvatinib and Pembrolizumab

Introduction: The efficacy of neoadjuvant lenvatinib plus pembrolizumab for clear cell renal cell carcinoma with inferior vena cava tumor thrombus remains unclear. Case Presentation: An 80-year-old man was diagnosed with clear cell renal cell carcinoma and tumor thrombus extending into the inferior vena cava. Following neoadjuvant lenvatinib plus pembrolizumab, the primary renal tumor shrank markedly, whereas the inferior vena cava tumor thrombus demonstrated only a slight reduction in size. Robot-assisted radical nephrectomy and lymphadenectomy were performed; however, conversion to open surgery was required because of an inferior vena cava laceration. Pathological examination revealed no residual viable cancer cells. The patient has remained free of recurrence for 1.5 years postoperatively. Conclusion: In this case, a pathological complete response was achieved following combination therapy of lenvatinib with pembrolizumab.