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 and plan your treatment.
TNM staging system
This gives information about the tumour, if it has spread to any lymph nodes, or to another part of the body (metastasis). T is for tumour, N is for nodes, and M is for metastasis.
Doctors put a number next to the T to describe the size and spread of the cancer.
- T1 and T2 tumours are known as early (localised) prostate cancer.
- T1 means the tumour is contained in the prostate and is too small to be felt when a doctor does a rectal examination or to be seen on a scan. The cancer may have been diagnosed by a biopsy to check a raised PSA level. Or it may have been diagnosed by chance after an operation to remove part of the prostate to make peeing easier.
- T2 means the tumour is still contained in the prostate, but your doctor can feel it when they do a rectal examination. T2 tumours are divided into:
- T2a – The tumour is only in half of one of the two lobes of the prostate.
- T2b – The tumour is in more than one half of one lobe.
- T2c – The tumour is in both lobes.
- T3 tumours have spread outside the prostate and may be growing into tissues or organs close by. T3 tumours are divided into:
- T3a – The tumour has spread through the capsule surrounding the prostate.
- T3b – The tumour has spread to the seminal vesicles that produce some of 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.
- 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.
- M0 means the cancer has not spread to another part of the body.
- 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.
The number staging system
There are a few different systems used for staging prostate cancer. A simplified number staging system is described below.
- Stage 1
The tumour is contained in the prostate. The tumour is too small to be felt when a doctor does a rectal examination or to be seen on a scan.
- Stage 2
The tumour is still contained in the prostate, but your doctor can feel it when they do a rectal examination.
- 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:
The grade of a cancer gives an idea of how quickly the cancer might grow or spread. A doctor decides the grade of the cancer by how the cancer cells look under the microscope.
Doctors look at the grade of the cancer to help them plan your treatment.
Gleason is the most commonly used grading system for prostate cancer.
This looks at the pattern of cancer cells in the prostate. There are 5 different patterns, graded from 1 to 5.
Grade 1 is very similar to normal prostate tissue, and grade 5 is very different to normal tissue. Only grades 3, 4, and 5 are cancer.
There may be more than one grade. The doctor examines all the samples taken at your biopsy. They find:
- the most common grade in the samples
- the highest grade in the samples.
They add these together to get your Gleason score. A Gleason score of 7 could be 3 + 4 or 4 + 3.
If your Gleason score is between 6 and 10:
- Gleason score 6
The cancer is slow-growing and less likely to spread.
- Gleason score 7
The cancer is between a slow-growing and fast-growing cancer (intermediate grade).
- Gleason score 8 to 10
The cancer is more likely to grow quickly and to spread (high grade).
New grading system
This new system grades the cancer between 1 and 5, depending on your Gleason score. The lower the grade, the less likely the cancer is to spread. This helps your doctor to plan your treatment.
There are 5 Grade Groups:
- Grade Group 1 (Gleason score 6) is the lowest grade and not likely to spread.
- Grade Group 2 (Gleason score 3 + 4 = 7).
- Grade Group 3 (Gleason score 4 + 3 = 7).
- Grade Group 4 (Gleason score 8).
- Grade Group 5 (Gleason scores 9 and 10).
This system splits Gleason score 3 + 4 and 4 + 3, although they both equal a score of 7. If your most common grade is 3 rather than 4, you are in Grade Group 2. Men in Grade Group 3 may need more treatment than men in Grade Group 2.
Gleason scores 8 to 10 are split into Grade Group 4 and Grade Group 5. Grade Group 5 cancers are more likely to spread quickly than Grade Group 4 cancers.