The bladder is a hollow muscular sac that stores urine. It is located in the pelvis and is part of the urinary system. As well as the bladder, the urinary system includes two kidneys, two tubes called ureters leading from the kidneys into the bladder, and another tube called the urethra leading out of the bladder. In women, the urethra is a short tube that opens in front of the birth canal (vagina). In men, the urethra is longer and passes through the prostate and down the penis.

The kidneys produce urine, which travels to the bladder through the ureters. The bladder is like a balloon and inflates as it fills. When it is time to go to the toilet, the bladder muscle contracts and urine is passed through the urethra and out of the body.

Bladder cancer begins when cells in the inner lining of the bladder become abnormal, which causes them to grow and divide out of control.

Bladder cancer begins when cells in the inner lining of the bladder become abnormal, which causes them to grow and divide out of control. The treatment for bladder cancer depends on how quickly the tumour cells are growing and how far the cancer has spread into the layers of the bladder.

There are three main types of bladder cancer. They are named after the cell type in which the cancer first develops.