The stage of a cancer means how big the cancer is and whether it has spread. Knowing the stage helps your doctor decide which treatment you need.
The tests you have to diagnose your bladder cancer help your doctor find out the stage.
The TNM staging system is the most common way that doctors stage bladder cancer. TNM stands for Tumour, Node, Metastasis.
Your doctor may call your bladder cancer non muscle invasive (early), invasive or advanced.
Doctors may also use a number staging system, but this is less common for bladder cancer.
Tumour describes the size of the tumour.
Doctors find the T stage by taking tissue samples (biopsies) to look at the grade of the cancer cells. The grade tells you how much the cancer cells look like normal cells. They also look at your bladder using a cystoscopy and a CT or MRI scan.
There are several T stages:
CIS or Tis means very early, high grade cancer cells are only in the innermost layer of the bladder lining.
Ta means the cancer is just in the innermost layer of the bladder lining.
T1 means the cancer has started to grow into the connective tissue beneath the bladder lining.
T2 means the cancer has grown through the connective tissue into the muscle. It is divided into T2a and T2b.
T2a means the cancer has grown into the superficial muscle
T2b means the cancer has grown into the deeper muscle
T3 means the cancer has grown through the muscle into the fat layer. It is split into T3a and T3b.
T3a means the cancer in the fat layer can only be seen under a microscope (microscopic invasion)
T3b means the cancer in the fat layer can be seen on tests, or felt by your doctor during an examination under anaesthetic (macroscopic invasion)
T4 means the cancer has spread outside the bladder. It is split into T4a and T4b.
T4a means the cancer has spread to the prostate, womb (uterus) or vagina
T4b means the cancer has spread to the wall of the pelvis or abdomen
Node in TNM means your lymph nodes. These are a network of glands throughout the body, for example in your armpits, neck and groin. They drain away waste fluid, waste products and damaged cells, and contain cells that fight infection.
Cancer cells can enter the lymphatic system and travel around the body.
The lymph nodes can be seen and measured on a CT scan or MRI scan. Or the surgeon may find them during surgery to remove your bladder if you have this operation.
There are 4 lymph node (N) stages in bladder cancer - N0 to N3:
- N0 means there are no cancer cells in any lymph nodes
- N1 means there are cancer cells in one lymph node in the pelvis (between your hip bones)
- N2 means there are cancer cells in more than one lymph node in the pelvis
- N3 means there are cancer cells in one or more lymph node just outside the pelvis
Your doctor may call your cancer 'locally advanced bladder cancer' if it has spread to nearby lymph nodes (stages N1-3).
Metastasis describes whether the cancer has spread to a different part of the body.
There are 2 M stages:
- M0 means your cancer has not spread to other parts of the body
- M1 means your cancer has spread to other parts of the body
M1 can be divided into M1a and M1b:
- M1a means your cancer has spread to the lymph nodes outside the pelvis
- M1b means your cancer has spread to other parts of the body like the bones, lungs and liver
Cancer that has spread to other areas of the body, such as the lungs, is called advanced or metastatic bladder cancer.
There is another staging system for bladder cancer which is not used often. It has 5 main stages, numbered from stage 0 to stage 4. Stage 0 is the earliest cancer and stage 4 is the most advanced.
The cancer is just in the inner layer of the bladder lining (stage 0a) OR there are very early, high grade cancer cells only in the inner layer of the bladder lining (stage 0is).
The cancer has started to grow into the connective tissue beneath the bladder lining.
The cancer has grown through the connective tissue layer into the muscle of the bladder wall.
The cancer has grown through the muscle into the fat layer and may have spread to the prostate, womb or vagina. It might also have spread to nearby lymph nodes.
The cancer has spread to the wall of the tummy (abdomen) or between the hips (pelvis), to distant lymph nodes or to other parts of the body such as the bones, lungs or liver.