What is bladder cancer?
Bladder cancer is when abnormal cells in the bladder lining start to grow and divide in an uncontrolled way. Your bladder is a hollow organ in the lower part of your tummy (abdomen) called the 
The bladder collects and stores your wee (urine).
The bladder
Your bladder is part of the body system that filters waste products out of your blood and makes urine (wee). This is called the urinary system (or urinary tract). It includes the:
- kidneys
- ureters
- bladder
- urethra
You have two kidneys, one on each side of your body. The kidneys filter your blood and make urine. The urine is carried to your bladder by two tubes called the ureters.
Your bladder is like a balloon which stores urine. It's a stretchy bag made of muscle tissue. It can hold about 300 to 400mls of urine.
When we empty our bladder, the urine passes down a tube called the urethra and out of the body. The urethra in men passes through the prostate gland and down the penis. The urethra in women is much shorter. It passes from the bladder down to an opening just in front of the vagina.
In men, the prostate gland surrounds the lower part of the bladder.
Layers of the bladder
Your bladder is made up of layers:
- The first layer is the lining on the inside of your bladder. It is called the transitional epithelium or urothelium.
- The second layer is a thin layer of connective tissue called the lamina propria.
- The third layer is muscle tissue called the muscularis propria.
- The fourth layer is fatty connective tissue. It separates the bladder from other body organs, such as the prostate and kidneys.
Doctors describe your bladder cancer based on how far it has spread through these layers. You can have:
- non muscle invasive bladder cancer - the cancer is only in the lining or the connective tissue beneath the bladder lining
- muscle invasive bladder cancer - the cancer has grown into the deeper (muscle) layer of the bladder, or beyond
Where bladder cancer starts
Most bladder cancers start in the inner lining of the bladder. This lining has 2 names:
- the transitional epithelium
- the urothelium
The bladder lining is made up of cells called transitional (urothelial) cells. Cancers that start in these cells are called transitional cell bladder cancers. Doctors also call them urothelial cancers.
Transitional (urothelial) cell bladder cancers are the most common type of bladder cancer. There are rare types of bladder cancer that start in different types of cell in the bladder.
How common is bladder cancer?
Around 10,300 people are diagnosed with bladder cancer in the UK every year. It's the 11th most common cancer in the UK, and the 8th most common cancer in men.
Who gets it?
Bladder cancer usually takes a long time to develop, so it is most common in older people. Almost 60 out of 100 (almost 60%) of new cases are in people aged 75 and over. It is rare in people under 40.
More men than women get bladder cancer. This may just be because more men than women have smoked or been exposed to chemicals at work in recent decades.
