Bladder cancer is classified into several different types depending on exactly where the problem started:
- Transitional cell bladder cancer, which starts in the bladder lining and is responsible for 90% of bladder cancers in the UK. It can be divided into invasive and non-muscle invasive cancers depending on the way the tumour grows.
- Squamous cell bladder cancer, which are often invasive and account for about 5% of cases in the UK.
- Adenocarcinoma, which starts in the mucous glands and causes 1-2% of cases.
- Rarer types include sarcomas and small cell cancers.
- Cancer can also spread to the bladder from other parts of the body.
Bladder cancer is typically staged by size and location according to the TNM system rather than the number system used for other cancers:
- T describes the size and location of the tumour and ranges from Ta when it is just in the bladder lining to the T4 stages when it has spread beyond the bladder
- N tells you whether cancer has been detected in your lymph nodes, ranging from N0 (none) to N3
- M relates to metastases, with M0 meaning that the cancer has not spread and M1 that there are secondary tumours in other parts of the body
The cancer cells will also be graded according to how different they look from your normal cells:
- Grade 1 cells look very normal and are likely to grow slowly without spreading far
- Grade 2 cells look somewhat abnormal and are more actively growing
- Grade 3 cells look very abnormal and tend to grow faster and be more invasive
Why the Diagnosis Matters for Bladder Cancer Treatment?