Prostate Cancer Knowledge Centre
Epidemiology and Classification
Classification
Pattern of disease spread
The most commonly used system for describing the pattern of disease spread in prostate cancer is the Tumour-Node-Metastasis (TNM) system.1 This describes the cancer in terms of the characteristics of the primary tumour (T), the involvement of regional lymph nodes (N) and the presence of distant metastases (M). Patient information on this topic can be found at Unitedagainstprostatecancer.com.
The 2009 TNM classification for PCa 1
| T– Primary tumour | ||
|---|---|---|
| TX | Primary tumour cannot be assessed | |
| T0 | No evidence of primary tumour | |
| T1 |  Clinically inapparent tumour not palpable or visible by imaging |
|
| T1a | Tumour incidental histological finding in ≤5% of tissue resected | |
| T1b | Tumour incidental histological finding in >5% of tissue resected | |
| T1c | Tumour identified by needle biopsy (e.g.because of elevated prostate-specific antigen levels) | |
| T2 |  Tumour confined within the prostate* |
|
| T2a | Tumour involves one half of one lobe or less | |
| T2b | Tumours involves more than one half of one lobe, but not both lobes | |
| T2c | Tumour involves both lobes | |
| T3 |  Tumour extends through the prostatic capsule† |
|
| T3a | Extracapsular extension (unilateral orbilateral) | |
| T3b | Tumour invades seminal vesicles | |
| T4 |  Tumour is fixed or invades adjacentstructures other than seminal vesicles: bladder neck, external sphincter,rectum, levator muscles or pelvic wall |
|
| N– Regional lymph nodes ‡ | ||
| NX | Regional lymph nodes cannot be assessed | |
| N0 | No regionallymph node metastasis | |
| N1 | Regional lymph node metastasis | |
| M– Distant metastasis § | ||
| MX | Distant metastasis cannot be assessed | |
| M0 | No distant metastasis | |
| M1 | Distant metastasis | |
| M1a | Non-regional lymph node(s) | |
| M1b | Bone(s) | |
| M1c | Other site(s) | |
*Tumour found in one or both lobes by needle biopsy, but not palpable or visible by imaging, is classified as T1c
†Invasion into the prostatic apex, or into (but not beyond) the prostate capsule, is not classified as T3, but as T2
‡Metastasis no larger than 0.2cm can be designated pN1mi
§When more than one site of metastasis is present, the most advanced category should be used
Images adapted from Kirby and Patel (2008)2
References:
1. European Association of Urology. Guidelines on prostate cancer, 2010.
2. Kirby RS, Patel MI. Fast facts: prostate cancer (5th ed). Health Press Ltd: Oxford, 2008.