Complete remission with tyrosine kinase inhibitors in renal cell carcinoma

In the era of cytokine therapy, although response rates of interleukin-2 (IL-2) in patients with metastatic renal cell carcinoma (m-RCC) were not satisfactory, a small percentage of complete remission (CR) was achieved (1). Recently, targeted therapy has replaced cytokine therapy. Sunitinib, a tyrosine kinase inhibitor (TKI), has been especially effective in tumor reduction but has rarely induced CR (1). Because of the unique and characteristic adverse effects (AEs) of targeted drugs, this study highlights the importance of maintaining therapy in patients who have achieved CR with TKIs. A multicenter study on m-RCC patients who achieved CR with either TKI (sorafenib, sunitinib) alone or in combination with local treatment (surgery, radiotherapy, radiofrequency ablation) was performed retrospectively. The subjects of the study were 64 patients who achieved CR: 36 were treated with TKI alone and 28 with TKI plus local treatment. The denominator of all patients treated with TKIs was not available, but the incidence of CR from a part of them was 1.7%. This rate is in line with data from other studies (1,2). The aim of this study is to characterize the patients, to assess the indication of discontinuing targeted therapy, and to define the subsequent therapeutic implications.