Cambridge prognostic groups and risk groups for prostate cancer

Doctors divide prostate cancer that hasn't spread into groups. This helps them recommend if you need treatment and the type of treatment you need. They use different systems to do this. These are:

• the Cambridge Prognostic Group (CPG)
• risk groups

In the UK, doctors now use the Cambridge Prognostic Group (CPG) for prostate cancer that hasn't spread. This divides prostate cancer into 5 prognostic groups. The term prognostic refers to your outlook (prognosis ). So your prognostic group tells you how likely it is that your cancer will grow or spread. And how likely it is that you will die from your cancer. 

There are 5 groups, from CPG1 to CPG5.

Some doctors may still use an older, different system. This divides prostate cancer into 3 risk groups. In this system, risk refers to how likely it is that cancer will come back after treatment. The groups are:

• low risk prostate cancer 
• medium or intermediate risk prostate cancer  
• high risk prostate cancer   

If your cancer has spread

When prostate cancer spreads to another part of your body, it is called metastatic prostate cancer. Doctors don't use prognostic groups or risk groups for prostate cancer that has spread. 

The Cambridge Prognostic Group system

Doctors look at your test results and scans to put you in a prognostic group from 1 to 5. They look at the:

• Grade Group or Gleason score

• prostate specific antigen (PSA) level at time of diagnosis

• tumour stage - this is the T stage from the TNM staging

Grade Groups

The Grade Groups tell you how much the cancer cells look like normal cells. A specialist doctor called a pathologist looks at several samples of cells from your prostate. These are biopsies.

They then grade each sample based on how quickly they are likely to grow and how aggressive the cells look. Grade Groups have replaced the older system called the Gleason score.

PSA level

PSA is a protein made by both normal and cancerous prostate cells. A PSA level higher than what would be expected for someone of your age can be a sign of prostate cancer.

Tumour (T) stage

The tumour stage describes how far the cancer has grown in the prostate. There are 4 main T stages of prostate cancer – T1 to T4.

This is a simplified description of the 4 T stages:

T1 means the cancer is too small to be seen on a scan or felt during an examination of the prostate.

T2 means the cancer is completely inside the prostate gland.

T3 means the cancer has clearly broken through the capsule (covering) of the prostate gland.

T4 means the cancer has spread into other organs nearby such as the bladder.

The 5 Cambridge Prognostic Groups

Below is a description of the 5 CPG groups. Ask your doctor or specialist nurse if you have any questions about your CPG group.

Cambridge Prognostic Group 1 (CPG 1)

You have:

• Grade Group 1 (previously called a Gleason score of 6)
• and a PSA level less than 10 nanograms per millilitre (ng/ml) 
• and a T stage of 1 or 2

Cambridge Prognostic Group 2 (CPG 2)

You have:

• Grade Group 2 (previously called a Gleason score of 3 + 4 = 7)
• or a PSA level between 10 and 20 ng/ml
• and a T stage of 1 or 2

Cambridge Prognostic Group 3 (CPG 3)

You have:

• Grade Group 2 (previously called a Gleason score of 3 + 4 = 7)
• and a PSA level between 10 and 20 ng/ml
• and a T stage of 1 or 2

Or

• Grade Group 3 (previously called a Gleason score 4 + 3 = 7)
• and a T stage of 1 or 2

Cambridge Prognostic Group 4 (CPG 4)

You have one of the following:

• Grade Group 4 (previously called a Gleason score of 8)
• PSA level higher than 20 ng/ml
• T stage of 3

Cambridge Prognostic Group 5 (CPG 5)

You have two or more of the following:

• Grade Group 4 (previously called a Gleason score of 8)
• PSA level higher than 20 ng/ml
• T stage of 3

Or

• Grade Group 5 (previously called Gleason score 9 to 10)

Or

• T stage of 4

The 3 risk groups system

Some doctors may still use an older system. This divides prostate cancer into 3 risk groups. The term risk refers to how likely it is that your cancer will come back after treatment.

But the National Institute for Health and Care Excellence (NICE) now recommends the CPG system instead. This is because research has found that the CPG is a more accurate way to group prostate cancer and make treatment decisions.

NICE is an independent organisation that provides guidance to the NHS in England to improve healthcare.

Ask your doctor if you aren’t sure about your stage, Gleason score and PSA level. Or if you have questions about your risk group. 

Low risk prostate cancer - doctors consider this to be similar to CPG 1.

Medium or intermediate risk prostate cancer - doctors consider this to be similar to CPG 2 and CPG 3.

High risk prostate cancer - doctors consider this to be similar to CPG 4 and CPG 5. 

Treatment for the Cambridge prognostic groups (CPGs)

Your CPG helps your doctor recommend if you need treatment. And if so, the type of treatment you need. Treatment also depends on:

• your age and general health

• how you feel about the treatments and side effects

If you have CPG 1 or CPG 2 prostate cancer

Your doctor might not recommend treatment straight away. Sometimes your doctor may recommend monitoring your cancer. You only start treatment if the cancer begins to grow. Depending on your situation, they may call this:

• active surveillance

• watchful waiting

Treatment is also an option if you have CPG 1 or 2 prostate cancer and you are not keen on monitoring. You can read more about treatment options below.

If you have CPG 3, CPG 4 or CPG 5 prostate cancer

Your doctor might recommend you have treatment. For cancer that hasn't spread, treatment might include:

• surgery to remove your prostate  - this is called a prostatectomy
• external radiotherapy with or without hormone therapy
• internal radiotherapy - this is called brachytherapy

If you have CPG 3 prostate cancer, your doctor might suggest active surveillance if you don’t want to have treatment straight away.  Doctors don't offer active surveillance to people with CPG 4 and 5 prostate cancer.

Treatment as part of a clinical trial

Some treatments are only available as part of a clinical trial. These include:

• high intensity focused ultrasound (HIFU) 
• cryotherapy 

Your doctor can tell you if one of these treatments might be an option for you.

If your cancer has spread

This is called metastatic prostate cancer.  You can read more about the treatment options in the section about metastatic prostate cancer.