4. STAGING AND CLASSIFICATION SYSTEMS
4.1. Pathological staging
For staging, the Tumour, Node, Metastasis (TNM) Classification (2017, 8th edition) is recommended [83]. Blood and lymphatic vessel invasion have an independent prognostic significance [84,85].
4.2. Tumour, node, metastasis classification
The TNM classification of malignant tumours is the method most widely used to classify the extent of cancer spread [83] (Table 4.1).
Table 4.1: TNM Classification of urinary bladder cancer [83]
| T - Primary Tumour | ||
| Tx | Primary tumour cannot be assessed | |
| T0 | No evidence of primary tumour | |
| Ta | Non-invasive papillary carcinoma | |
| Tis | Carcinoma in situ: “flat tumour” | |
| T1 | Tumour invades subepithelial connective tissue | |
| T2 | Tumour invades muscle | |
| T2a | Tumour invades superficial muscle (inner half) | |
| T2b | Tumour invades deep muscle (outer half) | |
| T3 | Tumour invades perivesical tissue: | |
| T3a | microscopically | |
| T3b | macroscopically (extravesical mass) | |
| T4 | Tumour invades any of the following: prostate stroma, seminal vesicles, uterus, vagina, pelvic wall, abdominal wall | |
| T4a | Tumour invades prostate stroma, seminal vesicles, uterus, or vagina | |
| T4b | Tumour invades pelvic wall or abdominal wall | |
| N - Regional Lymph Nodes | ||
| Nx | Regional lymph nodes cannot be assessed | |
| N0 | No regional lymph node metastasis | |
| N1 | Metastasis in a single lymph node in the true pelvis (hypogastric, obturator, external iliac, or presacral) | |
| N2 | Metastasis in multiple regional lymph nodes in the true pelvis (hypogastric, obturator, external iliac, or presacral) | |
| N3 | Metastasis in a common iliac lymph node(s) | |
| M - Distant Metastasis | ||
| M0 | No distant metastasis | |
| M1a | Non-regional lymph nodes | |
| M1b | Other distant metastasis | |
Staging after neoadjuvant chemotherapy (NAC) and RC can be done, but must be mentioned as ypTNM (International Collaboration on Cancer Reporting) [86]. ypT0N0 after NAC and cystectomy is associated with better prognosis [71,87,88].