[A Case of Metastatic Clear Cell Renal Cell Carcinoma Showing Long-Term Complete Response after the Discontinuation of Tyrosine Kinase Inhibitor].

Randomized phase III trials demonstrated superiority of targeted therapy with tyrosine kinase inhibitors over cytokine-based therapy as first-line therapy for metastatic renal cell carcinoma. However, the rate of complete response (CR) with targeted therapy is smaller than that with cytokine-based therapy. A 47-year-old man was referred to our hospital with a 12 cm left renal tumor and polycythemia. He was diagnosed with renal cancer, cT3aN0M1, with multiple lung metastases. He underwent cytoreductive nephrectomy, with the histopathological diagnosis of clear cell renal cell carcinoma, Fuhrman nuclear grade 2, INFb, pT2b. Three months postoperatively, spontaneous regression of lung metastases was observed. Seventeen months postoperatively, a 17×13 mm retroperitoneal tumor facing the pancreas recurred. CR of the recurrent tumor was achieved by targeted therapy with sunitinib for 12 months. This CR was maintained for 32 months after the discontinuation of targeted therapy with sunitinib.