A case of marked rectal stenosis due to Douglas' pouch metastasis of renal pelvic carcinoma successfully treated with salvage enfortumab vedotin: correlation between serum KL-6 levels and tumor response.

Enfortumab vedotin elicited a remarkable response in treating rectal stenosis due to metastasis of renal pelvic urothelial carcinoma in Douglas' pouch. Furthermore, serum KL-6 levels were correlated with the severity of metastatic urothelial carcinoma.