Staging and grading prostate cancer

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What are the grades of prostate cancer?

Grading helps your doctor to predict how the cancer will behave.

A doctor called a pathologist will look at samples of your prostate cells under a microscope. These are taken during the biopsy.

The pathologist will give the cells a grade. The grade is a number from 3 to 5 which describes how normal or abnormal the cells look. 

• A lower number means the cells look more like normal cells. 
• A higher number means they look less like normal cells.

Grading describes the cancer cells – what they look like and how they might grow.
Staging describes where the cancer is in your body – how big it is and if it has spread.

What is the Gleason score?

 The Gleason score will be described using a number from 6 to 10.  The pathologist will add the two most common grades together to make the Gleason score.

If the most common grade in the sample is 3, and the second most common grade in the sample is 4, then your Gleason score will be 7 (3+4). If only one grade is found, then this grade is added to itself. So if all the sample is only grade 3, then the Gleason score will be 6 (3+3).

Risk groups

Your doctor may describe your cancer as low, intermediate, high or very high risk, based on:

• Your Gleason score
• The stage of your cancer 
• Your PSA level 

The risk groups reflect the level of risk to your future health from the prostate cancer. 

Staging prostate cancer

Staging means finding out how big the cancer is and if it has spread to other parts of your body. Staging will help your doctor to plan the best treatment for you.

There are different ways to describe the stages of cancer. The TNM staging system refers to:

• The size of the tumour (T)
• If there is cancer in your lymph nodes (N)
• If the cancer has spread from where it started to other parts of your body (M for metastasis)

What are the stages of prostate cancer?

Tumour – How big is the tumour?

T1 The tumour is within your prostate gland. It is too small to be felt during a rectal exam.

T2 The tumour is still within your prostate gland. It is large enough to be felt during a rectal exam.

T3 The tumour can be felt throughout your prostate, and may have broken through the outer layer of the prostate.

T4 The tumour has spread to organs outside your prostate gland.

Node (N) – Are the lymph nodes affected or not?

N Cancer is present in the lymph nodes

N0 No cancer in the lymph nodes

N1 Cancer has spread to 1 or more of the lymph nodes

If you have been diagnosed with early prostate cancer you will see N0, meaning the cancer has not spread out of the prostate.

Metastasis (M) – has it spread outside the prostate?

M The cancer has spread to lymph nodes and/or other organs, commonly bones.

M0 The cancer has not spread

If you have been diagnosed with early prostate cancer you will see M0, as the cancer has not spread outside the prostate.