What is your preferred initial systemic therapy approach to metastatic clear cell adenocarcinoma of the urethra (CCAU)?

Clear cell adenocarcinomas of the urethra are very rare tumors, and the cell of origin remains unclear. These may arise from the urothelial lining, or alternatively the peri urethral glads or other stromal tissues. Given its rarity, it is not surprising that no standard treatment for metastatic dise...