[Clinical Investigation of Immune Checkpoint Inhibitor-Associated Kidney Injury in Patients with Urologic Cancers].

We investigated the clinical characteristics of patients who developed kidney injury after starting treatment with immune checkpoint inhibitors (ICI) for urologic malignancies. The study included 118 patients who were treated with ICI at our hospital. They consisted of 65 with renal cell carcinoma, 52 with urothelial carcinomas and 1 with adrenocortical carcinoma with high-frequency microsatellite instability. Immune-related kidney injury was observed in 13 patients (11.0%), including stage 1, 2 and 3 kidney injuries in 9, 0 and 4 patients, respectively. In univariate analyses, ≥stage 4 chronic kidney disease (CKD) before ICI treatment and proton pump inhibitor use were significantly associated with all stages of kidney injury, whereas ≥stage 4 CKD and ICI combination therapy were significantly associated with kidney injury at ≥ stage 2. Of the 4 patients who developed ≥stage 2 kidney injury, histological examination was done only for 2 because renal biopsy was contraindicated in the other 2 due to prior nephrectomy. Steroid pulse therapy was performed for 3 patients but provided complete recovery only in 1. We should be aware of the risk for immune-related kidney injury in patients with baseline CKD (≥stage 4) and receiving ICI combination therapy. Precise diagnosis by histological examination can often be challenging due to a history of nephrectomy.