The TNM system for staging prostate cancer
Two of the most commonly used staging systems are a numbered staging system and the TNM staging system. The TNM system is more detailed and is described below.
Doctors put a number next to the ‘T’ to describe the size and spread of the cancer.
The tumour is within the prostate gland. It is too small to be detected during a rectal examination, but may be picked up through tests such as a PSA test, a biopsy or a transurethral resection of the prostate gland (TURP) – an operation to make passing urine easier by removing part of the prostate gland. There are generally no symptoms with T1 tumours.
The tumour is still within the prostate gland but is large enough to be felt during a digital rectal examination, or it shows up on an ultrasound scan. Often there are no symptoms. The T2 stage is divided into three further parts:
T2a - The tumour is only in one half of one of the two that make up the prostate gland.
T2b - The tumour is in more than one half of one of lobes in the prostate gland.
T2c - The tumour is in both lobes of the prostate gland.
T1 and T2 tumours are known as early (localised) prostate cancer.
The cancer has begun to spread through the capsule that surrounds the prostate gland. The T3 stage is divided into two further parts:
T3a - The tumour has broken through the capsule but is not affecting the surrounding structures.
T3b - The tumour has spread into the glands that produce semen (seminal vesicles). These are very close to the prostate gland and sit just underneath the bladder.
The tumour has started to spread into nearby parts of the body such as the bladder or rectum.
T3 and T4 tumours are known as locally advanced prostate cancer because the cancer has started to spread outside the prostate gland and may be invading surrounding structures.
If the cancer has spread to other parts of the body, it’s known as metastatic, secondary, or advanced prostate cancer.
At the hospital you might also see the letters ‘N’ and ‘M’.
This describes whether there are any lymph nodes near the prostate gland that have cancer in them. The ‘N’ may have an ‘X’ or a number written next to it, which gives extra information about the nodes that were examined:
The lymph nodes were not examined.
The lymph nodes were examined but no cancer was found.
Cancer was found in the lymph nodes.
M stands for Metastasis
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Metastasis means that the cancer has spread to other parts of the body, such as the bones.
The ‘M’ may have a number written next to it, which gives extra information about where the cancer has spread to:
The cancer has not spread to other parts of the body.
The cancer has spread to another part of the body, such as the bones, lung or liver.
It’s important to talk to your doctor for detailed information about your situation. Our cancer support specialists on can also tell you more about TNM staging.