Once a cancer is scored as to how aggressive it is, it will then need to be assessed for how advanced it is i.e. the extent to which it has spread or not. This will help in deciding which treatment may be most effective. Prostate cancers are commonly given 4 stages (T1 to T4) depending on their development under a staging system known as TNM (tumour, nodes and metastases). hyperlink to EPC
TNM is made up of:
- The letter ‘T’ for tumour and a number
- The letter ‘N’ for lymph nodes
- The letter ‘M’ for metastasis or metastases
- T1 is for early prostate cancer that can only be seen under a microscope or by a high level of PSA in the blood. It is too small to be seen by the ultrasound scan and can’t be found by DRE. This called early or localised prostate cancer.
- T2 is for (localised) early cancer that can be seen on the ultrasound scan and the urologist or CNS will have been able to feel a lump or hard area when your prostate was examined during the DRE. This type of tumour is still contained inside the prostate and is also called early or localised prostate cancer.
- T3 is for cancer that has spread outside of the prostate (locally) but not to any extent. This can be seen on a scan and the urologist or CNS can feel it breaking through the wall of the prostate. If there is no evidence that the cancer has spread elsewhere in the body then this is called locally advanced prostate cancer.
- T4 is for cancer that has spread further beyond the prostate e.g. into other organs in the pelvis, back passage, the lymph nodes or the bones and started to grow in other sites. These sites are called metastases. This type of cancer is called advanced prostate cancer.
What does the ‘N’ stage mean?
The ‘N’ stands for lymph nodes. Lymph nodes help fight infection. Prostate cancer can spread to lymph nodes near the prostate or to lymph nodes in other parts of the body. So, the ‘N’ shows whether cancer has been found in the lymph nodes. This is measured during an MRI scan.
What does the ‘M’ stage mean?
The ‘M’ stands for metastasis (one other cancer site) or metastases (when there are several other cancer sites). This is the term used to measure the spread of the cancer in the body.
This is a test performed in the nuclear medicine department of your hospital. It is to find out if there is any evidence of spread of cancer cells to the bones, which is one of the common sites for prostate cancer to spread to.
For this test, you will be given an injection of a tiny amount of a substance called a radio-isotope into a vein. This may make you feel a bit hot or flushed for a minute or two. You will need to wait whilst the radio-isotope travels around your body and is taken up by any active cells in your bones. As this takes some time you may be able to leave the department then come back before the next step takes place. The radiologist (specialist X-ray doctor) or radiographer will then scan your whole body with a special machine called a gamma camera which detects radiation, and they will take pictures of your body.
The radiologist is looking to see if there are any ‘hot spots’. Hot spots are areas that take up a lot of radioactive material and this may indicate cancer. However, you can also get hot spots due to arthritis, broken bones and a condition called Page’s disease, so it is always worth mentioning these problems to the doctor if you have any of them.
Afterwards, it may be wise not to be in close contact with pregnant women, babies or young children until the day after the scan. Ask for more advice on this at your bone scan.
As this scan has to be studied in depth by a specialist, you won’t get the results straight away. The results will be sent to the doctor who referred you for the scan and it may take a few weeks.
An MRI (magnetic resonance imaging) scan is to help determine if there is any spread of prostate cancer outside of the prostate to other organs or tissues. (to see if the cancer is localised or locally advanced). It can also sometimes be used to look at the bones and the lymph nodes. Some men may be offered an MRI scan prior to having a biopsy.
The test is done in the X-ray department, but rather than using X-rays it uses radio-waves controlled by a powerful magnet to produce an image. Before an MRI scan the radiologist or radiographer will go through a checklist asking about any metal implants, such as a pacemaker, to make absolutely sure that the scan will not harm you in any way. You will be asked to take off any jewellery or metal objects. You will be asked to lie on a flat table, perhaps supported with pillows, to help you stay in the correct position and the radiographer may ask you to hold your breath at some points while the pictures are taken. The table will travel in and out of a tube containing these magnets whilst pictures are taken. You will not feel anything but some people who suffer from claustrophobia may find this test difficult.
The MRI scan usually takes about 30-40 minutes and the results will be back in a few weeks.
This is done less often now and usually only if you suffer from claustrophobia (fear of being in an enclosed space). A CT (computerised tomography), or CAT scan, is usually done to find out if there is any evidence of prostate cancer in the lymph nodes in the pelvis or the area around your prostate. Lymph nodes become swollen in infections, but also in response to spread from cancer cells. (The function of the lymph nodes is to clean the body fluids known as lymph to remove any problems).
A CT scan is done in the X-ray department and works by taking a series of X-ray pictures of the body from many different angles. The pictures are fed into a computer to obtain a 3D picture. A special dye is injected into a vein which might make you feel a bit hot for a few minutes. Then you will need to lie still on a flat table so the pictures aren’t blurred. The table will slide in and out through scanner, quickly at first then more slowly as you are X-rayed. You will hear a slight, buzzing, clicking and whirring sound as the CT scanner turns around you. You will be given instructions about holding your breath and when to breathe.
The CT scan usually takes about 30 minutes and the results will be back in about 1-2 weeks.