Stage 0is includes: Tis, N0, M0. Tis: For male penile urethra and female urethra: Carcinoma in situ. For prostatic urethra: Carcinoma in situ involving the prostatic urethra or periurethral or prostatic ducts without stromal invasion. N0: No regional lymph node metastasis. M0: No distant metastasis. (AJCC 8th ed.) [from NCI]