TNM staging for prostate cancer

The stage of prostate cancer tells you how far it has spread. TNM is a way of staging prostate cancer. It stands for Tumour, Node and Metastasis. 

Doctors in the UK now use a tool called the Cambridge Prognostic Group (CPG). This divides prostate cancer into 5 groups. This helps them recommend if you need treatment and the type of treatment you need. The CPG uses information about:

• the T stage from the TNM staging

• Grade Groups or Gleason score

• Prostate specific antigen (PSA) level

Read about the Cambridge Prognostic Group system (CPG)

It's important to know that the CPG system does not apply if you have cancer that has already spread to other parts of the body. This is metastatic or advanced prostate cancer.

Find out more about metastatic prostate cancer

Tumour (T)

Tumour describes the size or area of the cancer. This is a simplified description of the T stage.

There are 4 main T stages of prostate cancer – T1 to T4.

T1

T1 means the cancer is too small to be seen on a scan, or felt during an examination of the prostate. It’s divided into T1a, T1b and T1c.

• T1a means that the cancer is in less than 5% of the removed tissue.

• T1b means that the cancer is in 5% or more of the removed tissue.

Your surgeon might find a T1a or T1b cancer during surgery for other reasons. 

• T1c cancers are found by ​biopsy​ , for example after a raised PSA level.

T2

T2 means the cancer is completely inside the prostate gland.

Doctors regularly update TNM staging systems. The latest version no longer divides T2 into sub stages if your doctor stages the cancer after surgery. 

If you don't have surgery, your doctor might tell you you have T2a, T2b or T2c.

• T2a means the cancer is only in half of one side (​lobe​ ) of the prostate gland.

• T2b means the cancer is in more than half of one lobe of the prostate gland. But it is not in both sides. 

• T2c means the cancer is in both lobes but is still inside the prostate gland.

Ask your doctor or specialist nurse what the sub stage means in your case if you are told about them. 

T3

T3 means the cancer has broken through the capsule (covering) of the prostate gland. It’s divided into T3a and T3b.

• T3a means the cancer has broken through the capsule (covering) of the prostate gland.

• T3b means the cancer has spread into the tubes that carry semen (seminal vesicles).

T4

T4 means the cancer has spread into other body organs nearby, such as the back passage, bladder, or the pelvic wall.