A pathological complete response and adrenal insufficiency in a patient with advanced renal pelvic cancer treated with pembrolizumab.

Metastatic upper tract urothelial carcinoma (mUTUC) often has poor prognosis. While systemic therapy is the standard care for mUTUC, lymph node dissection (LND) combined with radical nephroureterectomy (RNU) can be considered for patients with only clinical locoregional LN, resulting in a surgical cure. However, since pembrolizumab, an anti-PD-1 monoclonal antibody, was approved for mUTUC patients, prognosis of mUTUC has been improved and some patients with immune-related adverse events have experienced a clinical complete response and a long-lasting therapeutic response without surgery. Thus, clarifying the optimal patient selection and timing for RNU + LND is warranted to avoid unnecessary surgery. We herein report the first unique case with a clinical N + UTUC patient who underwent RNU plus LND and showed a pathological complete response after discontinuation of pembrolizumab due to adrenal insufficiency. We feel that our case may affect the treatment strategy for N + UTUC in the era of ICIs.