Grading and staging for invasive and advanced bladder cancer
The grade of a cancer gives an idea of how quickly it may develop. To find the grade of your cancer, your doctors will look at a sample of the cancer cells under the microscope. It may be graded as:
Grade 1 - The cancer cells tend to grow slowly and look quite similar to normal cells (ie are ‘well differentiated’). They are less likely to spread than grade 2 or grade 3 cancers.
Grade 2 - The cancer cells look more abnormal and grow slightly more quickly than grade 1.
Grade 3 - The cancer cells tend to grow more quickly, look very abnormal (are ‘poorly differentiated’) and are more likely to spread.
Invasive bladder cancers are usually grade 2 or grade 3.
Another grading system classes invasive bladder cancer as either ‘low grade’ or ‘high grade’. Low-grade cancers are slower growing and less likely to spread than high-grade bladder cancers.
A cancer’s stage describes its size and whether it has spread. Once your doctors know the stage of the cancer, they can decide on the most appropriate treatment for you. A common staging system uses numbers to indicate the stage of the cancer.
There is a small area of cancer only in the bladder lining.
Stage 0is or CIS (carcinoma in situ)
This is sometimes described as a flat tumour. The cancer cells are confined to the inside layer of the lining of the bladder.
The cancer has grown into the layer of connective tissue beneath the bladder lining.
The cancer has grown into the muscle of the bladder wall under the connective tissue layer.
The cancer has grown through the muscle of the bladder and into the fat layer surrounding it. It may have spread to the prostate, womb or vagina.
The cancer has spread to the wall of the abdomen or pelvis, the lymph nodes or to other parts of the body. If bladder cancer spreads to other parts of the body, it will most likely go to the lungs, liver or bones.
Cross-section of the bladder wall showing the different tumour stages in the bladder
Others terms used
Early, superficial or non-muscle invasive bladder cancer refers to stage 0a, stage 0is (CIS) and stage 1 bladder cancers.
Invasive bladder cancer refers to stage 2 and stage 3 bladder cancers.
Advanced bladder cancer refers to stage 4 bladder cancer.
Metastatic bladder cancer means the cancer has spread to other parts of the body.
Another commonly used staging system for bladder cancer is called the TNM system:
T is the size of the tumour (cancer).
N is whether it has spread to the nearby lymph nodes (sometimes called glands).
M is whether the cancer has spread to other parts of the body (metastases).