How the cancer is treated will depend on its grade and stage.
Cancer grade: The grade gives an idea of how quickly the cancer may develop. The Gleason scoring system (see below) is used to grade prostate cancer. Low-grade, or low-risk, prostate cancer usually grows slowly and is less likely to spread. Higher grade prostate cancer may be more likely to grow quickly and spread to other body parts.
Cancer stage: Stage is a term used to describe the cancer’s size and the extent of its growth within or beyond the prostate. That is, how far it has spread.
Grading: the Gleason Score
Normal tissue has an ordered pattern of growth, but in cancer tissue the pattern is not ordered because of the unpredictable way cancer cells grow. The Gleason scoring system is used to show how abnormal or different the cancer tissue is, when compared with normal tissue. The two most common patterns of growth seen in the biopsy sample are each given a number from 1 to 5, and then these two numbers are added together to give the Gleason score (e.g. 4+3=7). The greater the difference from the normal tissue pattern, the higher the Gleason Score, the more aggressive the cancer acts in the body. The lowest Gleason score of a cancer that can be found on a prostate biopsy is 6.
As well as using the Gleason score system to grade prostate cancer, the doctor can tell the stage of the cancer.
Staging: the Tumour-Node-Metastasis (TNM) System
The TNM system is used to determine the stage of the cancer – that is, how far it has spread from the prostate. The TNM system has three scores:
- T (tumour) Stage: By doing a digital rectal examination (DRE), the doctor can feel if the tumour is in the prostate or whether it has spread just outside the prostate and into nearby areas. An MRI scan can also be used for this purpose.
- N (node) Stage: This shows if the cancer has spread to nearby lymph nodes in the pelvic region. A CT (computerised tomography) or MRI (magnetic resonance imaging) scan is used for this purpose.
- M (metastasis) Stage: This shows if the cancer has spread to other parts of the body such as bones. A bone scan is used for this purpose.
This information combined with the Gleason score informs decisions about the best treatment approach.
Prostate cancer tumour stages
The tumour or cancer cannot be felt by the doctor during examination
The cancer can be felt but it has not spread outside of the prostate
The cancer has spread outside of the prostate into nearby tissues
The cancer has spread into nearby organs such as the bladder
Listed below are some questions that may be useful to ask members of the healthcare team about the diagnostic:
- What are the results? What do they mean?
- What is the biopsy result? What does it mean?
- What is the prostate cancer stage? Can you please explain it?
- What is the Gleason Score? Can you please explain them?
- Are more tests needed? Can you please explain them?
- Where can we get more information about prostate cancer, support and care?
These are not the only questions to ask, there may be others that are more useful. The important thing is to get information about the diagnosis and how to support your partner or the person you're caring for
Different stages of prostate cancer
The stage of prostate cancer depends on whether the cancer has spread outside the prostate or not.
When the cancer is found only in the prostate gland, this is known as localised prostate cancer or early prostate cancer.
For some men, their prostate cancer grows slowly and is not aggressive. But in other men, the type of cancer grows more quickly and spreads to other parts of the body – this is called advanced prostate cancer.
There are different stages of advanced prostate cancer:
- Locally advanced: the cancer has extended beyond the prostate and may include seminal vesicles (tumour stage T3) or other surrounding organs such as the bladder or rectum (tumour stage T4)
- Metastatic: the cancer has spread to distant parts of the body such as bone.
Metastatic: the cancer has spread to distant parts of the body such as bone.
Click here to learn more about advanced prostate cancer.