Staging, grading and risk groups for prostate cancer

The stage of a cancer describes its size and how far it has spread. The results of your tests help your doctors decide on the stage.

Doctors often use the TNM staging system or a number staging system for prostate cancer.

We understand that waiting to know the stage and grade of your cancer can be a worrying time. We're here if you need someone to talk to. You can: 

• Call the Macmillan Support Line on 0808 808 00 00. 
• Chat to our specialists online. 

This gives information about:

• the tumour (T)
• whether the cancer has spread to any lymph nodes (N)
• whether the cancer has spread to another part of the body, called metastasis (M).

Tumour

Doctors put a number next to the T to describe the size and spread of the cancer.

• T1 – the tumour is contained in the prostate. It is too small to be felt on a rectal examination or seen on a scan. It may have been diagnosed by a biopsy for a raised PSA level. Or, it may have been diagnosed by chance after surgery to remove part of the prostate to make peeing (passing urine) easier.
• T2 – the tumour is still contained in the prostate. But it can be felt when the doctor does a rectal examination or is seen on a scan. T2 tumours are divided into:

• T2a – the tumour is only in half of 1 of the 2 lobes of the prostate
• T2b – it is in more than half of 1 lobe
• T2c – it is in both lobes.

T1 and T2 tumours are not likely to affect the lymph nodes or to spread. Doctors call this early or localised prostate cancer.

• T3 tumours have spread outside the prostate and may be growing into tissues close by:
  • T3a – the tumour has spread through the capsule surrounding the prostate.
  • T3b – the tumour has spread to the seminal vesicles that produce the fluid for semen.
• T4 tumours have spread into areas close by, such as the bladder or back passage (rectum), or the muscle that controls peeing (passing urine).

T3 and T4 cancers are called locally advanced prostate cancer.

When the cancer has spread to another area, it is called advanced or metastatic prostate cancer.

Nodes

• N0 means there is no cancer in the lymph nodes near the prostate.
• N1 means there is cancer in 1 or more lymph nodes close by.

Metastasis

• M0 means the cancer has not spread to another part of the body, so locally advanced prostate cancer is always M0.
• M1 means the cancer has spread to another part of the body, so advanced prostate cancer is always M1.

With the TNM staging system, advanced or metastatic prostate cancer can be any T, any N, and always M1.

You can talk to your doctor or specialist nurse about your TNM staging. They can explain it to you.

Number staging brings together different parts of the TNM staging system and gives it a number stage.

• Stage 1
  The tumour is contained in the prostate.
• Stage 2
  The tumour is bigger but still contained to the prostate.
• Stage 3
  The tumour has started to break through the outer capsule of the prostate and may be in the nearby tubes that produce semen (seminal vesicles).
• Stage 4
  The tumour has spread outside the prostate. It may have spread to areas such as the bladder or back passage (rectum). Or it may have spread further, for example to the bones.

Using the numbered staging system described above:

• stage 1 and stage 2 cancer is called early (localised) prostate cancer
• stage 3 and stage 4 cancer that has not spread to other parts of the body is called locally advanced prostate cancer
• stage 4 cancer which has spread to other parts of the body usually the bones is called advanced (metastatic) prostate cancer.

Prostate cancer is divided into risk groups.

Before planning your treatment, your cancer doctor will look closely at your risk group. This helps you and your doctors to decide on the best treatment for you. The treatment options for each risk group can be different.

Prostate cancer was previously grouped into low, intermediate or high risk groups. Doctors now use a more detailed system to work out your risk group. This is called the Cambridge Prognostic Group (CPG). It divides prostate cancer risk into 5 different groups. Your doctor may still describe your risk as low, moderate or high.

To work out your CPG risk group, your doctors look at:

• the stage of the cancer
• your PSA level (measured in nanograms per millilitre or ng/ml)
• your Gleason score.

The 5 different CPG risk groups are:

CPG 1

The cancer has all of the following:

• Stages T1
• PSA less than 10 ng/ml
• Gleason score 6 (grade group 1).

CPG 2

The cancer is Stages T1 -T2 and either:

• PSA 10- 20 ng/ml

or

• Gleason score 3 + 4 = 7 (grade group 2).

CPG 3

The cancer is Stage T1 -T2 and both:

• PSA 10- 20 ng/ml
• Gleason score 3 + 4 = 7 (grade group 2)

Or, the cancer is:

• Stages T1–T2

and

• Gleason 4 + 3 = 7 (grade group 3).

CPG 4

The cancer has 1 of the following:

• Stage T3
• PSA more than 20 ng/ml
• Gleason score 8 (grade group 4).

CPG 5

The cancer has 2 or more of the following:

• Stage T3
• PSA more than 20 ng/ml
• Gleason score 8 (grade group 4).

Or, the cancer is either of the following:

• Stage T4
• Gleason score 9 to 10 (grade group 5).