4. STAGING AND CLASSIFICATION SYSTEMS
4.1. Tumour, Node, Metastasis classification
In males and females, urethral carcinoma is classified according to the 9th edition of the Tumour, Node, Metastasis (TNM) classification [7] (Table 4.1). There is a separate TNM staging system for prostatic UC [7]. Of note, for cancers occurring in the urethral diverticulum, stage T2 is not applicable, as urethral diverticula are lacking periurethral muscle [32].
Table 4.1: TNM classification (9th edition) for urethral carcinoma [7]
| TNM classification (9th edition) for urethral carcinoma | |
| T - Primary tumour | |
| TX | Primary tumour cannot be assessed |
| T0 | No evidence of primary tumour |
| Urethra (male and female) | |
| Ta | Non-invasive papillary, polypoid, or verrucous carcinoma |
| Tis | Carcinoma in situ |
| T1 | Tumour invades subepithelial connective tissue |
| T2 | Tumour invades any of the following: corpus spongiosum, prostate, periurethral muscle |
| T3 | Tumour invades any of the following: corpus cavernosum, beyond prostatic capsule, anterior vagina, or bladder neck (extraprostatic extension) |
| T4 | Tumour invades other adjacent organs (invasion of the bladder) |
| Urothelial carcinoma of the prostate and prostatic urethra | |
| Tis pu | Carcinoma in situ, involvement of prostatic urethra |
| Tis pd | Carcinoma in situ, involvement of prostatic ducts |
| T1 | Tumour invades subepithelial connective tissue (for tumours involving prostatic urethra only) |
| T2 | Tumour invades any of the following: prostatic stroma, corpus spongiosum, periurethral muscle |
| T3 | Tumour invades any of the following: corpus cavernosum, beyond prostatic capsule, or bladder neck (extraprostatic extension) |
| T4 | Tumour invades other adjacent organs (invasion of the bladder or rectum) |
| N - Regional lymph nodes | |
| NX | Regional lymph nodes cannot be assessed |
| N0 | No regional lymph node metastasis |
| N1 | Metastasis in a single lymph node |
| N2 | Metastasis in multiple lymph nodes |
| M - Distant metastasis | |
| M0 | No distant metastasis |
| M1 | Distant metastasis |
4.2. Tumour grade
Nonurothelial urethral carcinoma is graded by a trinomial system that differentiates between well differentiated (G1), moderately differentiated (G2) and poorly differentiated (G3) tumours. In primary UC, histological subtypes are extremely rare. Table 4.2 lists the various grading systems according to the World Health Organization (WHO) 2022 system [33].
Table 4.2: Histopathological grading of urothelial and non-urothelial primary urethral carcinoma [33]
| Urothelial urethral carcinoma | |
| PUNLMP | Papillary urothelial neoplasm of low malignant potential |
| Low grade | Well differentiated |
| High grade | Poorly differentiated |
| Non-urothelial urethral carcinoma | |
| Gx | Tumour grade not assessable |
| G1 | Well differentiated |
| G2 | Moderately differentiated |
| G3 | Poorly differentiated |
4.3. Handling of tumour specimens
Specimen handling should follow the general rules as published by the International Collaboration on Cancer Reporting (ICCR) [34].
Table 4.3: Required and recommended elements for pathology reporting of carcinoma of the urethra in urethrectomy specimens [7, 34]
| Required | Recommended | ||
| Operative procedure | Clinical information | Previous history of urinary tract disease or distant metastasis | |
| Additional specimens submitted | Previous therapy | ||
| Maximum tumour dimension | Cannot be assessed | Other clinical information | |
| No macroscopically visible tumour | Tumour focality | ||
| Maximum tumour dimension (largest tumour) | Other tumour dimensions (than maximum dimension) of the largest tumour | ||
| Macroscopic tumour site | Block identification key | ||
| Macroscopic extent of invasion | Associated epithelial lesions | ||
| Histological tumour type | Histological subtype/variant (urothelial carcinoma) | Extranodal spread for involved regional lymph node(s) | |
| Non-invasive carcinoma | Coexistent pathology | ||
| Histological tumour grade | Ancillary studies | ||
| Microscopic extent of invasion | |||
| Lymphovascular invasion | |||
| Margin status | |||
| Regional lymph node status | No regional lymph nodes submitted | ||
4.4. Recommendation for staging and classification systems
| Recommendation | Strength rating |
| Use the 2025 Tumour, Node, Metastasis classification and 2022 World Health Organization grading system for pathological staging and grading of primary urethral carcinoma. | Strong |