The stages of prostate cancer

The stage of a cancer tells the doctor how far the cancer has spread. The tests and scans you have when diagnosing your cancer give some information about the stage. It is important because knowing the stage helps doctors decide on which treatment you need.

Prostate cancer is staged using the TNM system. This is used all over the world. It separately assesses the tumour (T), lymph nodes (N) and secondary cancer (metastases – M).

T (tumour) staging

T1 tumours are too small to be seen on scans or felt during examination of the prostate – they may have been discovered by needle biopsy, after finding a raised PSA level

T2 tumours are completely inside the prostate gland and are divided into 3 smaller groups

• T2a – The tumour is in only half of one of the lobes of the prostate gland
• T2b – The tumour is in more than half of one of the lobes
• T2c – The tumour is in both lobes but is still inside the prostate gland

T3 tumours have broken through the capsule (covering) of the prostate gland but have not spread into other organs – they are divided into 2 smaller groups

• T3a – The tumour has broken through the capsule (covering) of the prostate gland
• T3b – The tumour has spread into the seminal vesicles

T4 tumours have spread into other body organs nearby, such as the rectum (back passage), bladder, muscles or the sides of the pelvic cavity

Stage T3 and T4 tumours are referred to as locally advanced prostate cancer.

N (lymph node) staging

Lymph nodes are described as being 'positive' if they contain cancer cells. If a lymph node has cancer cells inside it, it is usually bigger than normal. The more cancer cells it contains, the bigger it will be.

• NX – The lymph nodes cannot be checked
• N0 – There are no cancer cells in lymph nodes close to the prostate
• N1 – There are cancer cells present in lymph nodes

M staging – metastases (cancer spread)

• M0 – No cancer has spread outside the pelvis
• M1 – Cancer has spread outside the pelvis
• M1a – There are cancer cells in lymph nodes outside the pelvis
• M1b – There are cancer cells in the bone
• M1c – There are cancer cells in other places

Example of staging

So, a cancer described as T2 N0 M0 is 

• A cancer that is entirely within the prostate
• With no cancer spread to lymph nodes
• And no spread of the cancer to areas outside the pelvis

This way of staging takes into account the size of the tumour, whether there are cancer cells in lymph glands (also called lymph nodes) close to the prostate gland, and whether the tumour has spread anywhere else.

Prostate cancer has four basic stages which are

• Stage 1 – the cancer is very small and completely inside the prostate gland, which feels normal during a rectal examination
• Stage 2 – the cancer is still inside the prostate gland, but is larger and a lump or hard area can be felt during a rectal examination
• Stage 3 – the cancer has broken through the covering of the prostate and may have grown into the tubes which carry semen
• Stage 4 – the cancer has grown into the bladder or rectum, or has spread to the lymph nodes or another part of the body, such as the bones, liver or lungs

Prostate cancer most commonly spreads to the bones. It can spread to other organs though. With prostate cancer, it is sometimes possible to have metastases (cancer spread) present even when the prostate tumour is still very small. So even if the tumour appears to be very small, when a bone scan shows that there is cancer in the bones, the prostate cancer is M1 stage. It will be treated as advanced, metastatic cancer. Advanced cancer can often be controlled for several years with treatment.

If you would like to talk to someone about the stages of prostate cancer, you can contact one of the prostate cancer organisations. You can also contact our cancer information nurses. They would be happy to help.