Diagram of the staging of prostate cancer

The TNM staging system is the most common way that doctors stage prostate cancer. TNM stands for Tumour, Node, Metastasis.

Tumour (T)

Tumour describes the size of the tumour (area of cancer). This is a simplified description of the T stage. There are 4 main stages of cancer size in prostate cancer - T1 to T4.

TX means the main cancer (primary) can't be assessed.

T0 means there is no sign of cancer.

T1 - cancer is too small to be seen on a scan, or felt during examination of the prostate

T1a - cancer is in less than 5% of the removed tissue

T1b - cancer is in or more than 5% of the removed tissue

T1c cancers are found by biopsy, for example after a raised PSA level

T2 - the cancer is completely inside the prostate gland

T2a - the cancer is in only half of one side of the prostate gland

T2b - the cancer is in more than half of one side of the prostate gland

T2c - the cancer is in both sides but is still inside the prostate gland

T3 - the cancer has broken through the capsule of the prostate gland

T3a - the cancer has broken through the capsule of the prostate gland

T3b - the cancer has spread into the seminal vesicles

T4 means the cancer has spread into other body organs nearby, such as the back passage, bladder, or the pelvic wall.

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Node (N)

Node (N) describes whether the cancer has spread to the lymph nodes.

NX means that the lymph nodes cannot be assessed

N0 the nearby lymph nodes do not contain cancer cells

N1 means there are cancer cells in lymph nodes near the prostate

Metastasis (M)

There are 2 stages of metastasis - M0 and M1

M0 means the cancer has not spread to other organs.

M1 - the cancer has spread to other parts of the body outside the pelvis

M1a - cancer cells in lymph nodes outside the pelvis

M1b - the cancer has spread to bone

M1c - the cancer has spread to other sites