Prostate cancer risk groups and the Cambridge Prognostic Group (CPG)

Doctors group prostate cancer into risk groups. Your risk group tells you how likely it is that the cancer will grow quickly or spread. This helps your doctor recommend if you need treatment and the type of treatment you need.

In the UK, doctors now divide localised and locally advanced prostate cancer into 5 risk groups. This is the Cambridge Prognostic Group (CPG). The 5 risk groups are from CPG1 to CPG5.

Some doctors may still use an older system that divides prostate cancer into 3 risk groups. These are:

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

The Cambridge Prognostic Group system

Doctors look at the results of your tests and scans to give you a score from 1 to 5. They look at the:

  • Grade Group or Gleason score
  • prostate specific antigen (PSA) level
  • tumour stage. This is from the T stage from the TNM staging
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.

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.

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 stage

The tumour stage describes the size of the tumour or area of the cancer. 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 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:

  • a Gleason score of 6. This is Grade Group 1
  • 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:

  • a Gleason score of 3 + 4 = 7. This is Grade Group 2
  • 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:

  • a Gleason score of 3 + 4 = 7. This is Grade Group 2
  • and a PSA level between 10 and 20 ng/ml
  • and a T stage of 1 or 2

Or

  • a Gleason score 4 + 3 = 7. This is grade group 3
  • and a T stage of 1 or 2

Cambridge Prognostic Group 4 (CPG 4)

You have one of the following:

  • Gleason score of 8. This is Grade Group 4
  • 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:

  • Gleason score 8. This is Grade Group 4
  • PSA level higher than 20 ng/ml
  • T stage of 3

Or

  • Gleason score 9 to 10. This is Grade Group 5

Or

  • T stage of 4

The 3 risk groups system

Some doctors may still use an older system that divides prostate cancer into 3 risk groups. 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 assess prostate cancer.

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

Your cancer is low risk if you have all of the following:

  • T stage of T1 to T2a
  • Gleason score no higher than 6
  • PSA level less than 10 ng/ml

This is similar to CPG 1.

Medium or intermediate risk prostate cancers

Your cancer is medium risk if you have one of the following: 

  • T stage of T2b
  • Gleason score of 7
  • PSA level between 10 and 20 ng/ml

This is similar to CPG 2 and CPG 3.

High risk prostate cancer

Your cancer is high risk if you have one of the following: 

  • T stage of T2c
  • Gleason score between 8 and 10
  • PSA level higher than 20 ng/ml

This is similar to CPG 4 and CPG 5.

Treatment

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

  • your age and general health
  • how you feel about the treatments and side effects

You might not have treatment straight away if you are in the CPG 1, 2 or 3. Sometimes your doctor monitors your cancer and starts treatment if the cancer begins to grow. Depending on your situation, they may call this:

  • active surveillance
  • watchful waiting

Your doctor might recommend you have treatment if you are in the CPG 2, 3, 4 or 5. Treatment might include:

  • surgery to remove your prostate
  • external radiotherapy
  • internal radiotherapy (brachytherapy)
  • hormone therapy
  • chemotherapy
  • symptom control treatment
  • high frequency ultrasound therapy (HIFU) as part of a clinical trial
  • cryotherapy as part of a clinical trial
Last reviewed: 
24 May 2022
Next review due: 
24 May 2025
  • Using the Cambridge Prognostic Groups for risk stratification of prostate cancer in the National Prostate Cancer audit: How could it impact our estimates of potential ‘over-treatment’?
    National Prostate Cancer Audit, 2021

  • Prostate cancer: diagnosis and management
    National Institute for Health and Care Excellence (NICE), 2019. Last updated December 2021

  • The Cambridge Prognostic Groups for improved prediction of disease mortality at diagnosis in primary non-metastatic prostate cancer: a validation study
    V J Gnanapragasam and others
    BMC Medicine, 2018. Vol 16, Issue 31

  • Risk stratification for prostate cancer management: value of the Cambridge Prognostic Group classification for assessing treatment allocation
    M G Parry and others
    BMC Medicine, 2020. Vol 18, Issue 114

  • AJCC Cancer Staging Manual (8th Edition)
    American Joint Committee on Cancer, 2017

  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. Please contact patientinformation@cancer.org.uk with details of the particular issue you are interested in if you need additional references for this information.

Related links