I believe I have the same rare cancer. Mucin producing urothelial adenocarcinoma with urethra primary and prostate involvement. Various Mets. On Keytruda, ivermectin and 5-FU. CEA has dropped from 30.7 to 3.8 and symptoms are improving. Tumor is PDL-1 positive at 100. Would like to compare notes and share info as this is a very rare tumor.