Complete response of renal cell carcinoma with an inferior vena cava tumor thrombus and lung metastases after treatment with nivolumab plus ipilimumab

In recent years, immune checkpoint inhibitors have become the most important drugs for treating renal cell carcinoma. In combination with performing nephrectomies, tyrosine kinase inhibitors have been used as neoadjuvant therapy, as they reduce the size of a primary renal mass and cause the disappearance of metastatic lesions. However, there are only a few reports on immune checkpoint inhibitors as neoadjuvant therapy. Herein, we report a case of renal cell carcinoma with multiple lung metastases and an inferior vena cava tumor thrombus that showed a complete response via radical nephrectomy after nivolumab plus ipilimumab. A 47-year-old man was diagnosed with renal cell carcinoma with multiple lung metastases and inferior vena cava tumor thrombus. After four treatment cycles of nivolumab plus ipilimumab and five cycles of nivolumab, we performed radical nephrectomy and resection of the thrombus tumor by excising a part of the inferior vena cava. The pathological diagnosis had no residual tumor. To our knowledge, this is the first case of complete disappearance of all malignant cells. Immunostaining of the primary renal mass revealed strong positivity for CD4 and CD8. The patient has been followed up without additional treatment for 8 months, but no recurrence has been observed. We suggest the use of nivolumab plus ipilimumab as neoadjuvant therapy. However, physicians should consider the possibilities of immune-related adverse events.