Bladder Cancer Health Center
Your bladder is a hollow organ in the lower abdomen. It stores urine, the liquid waste made by the kidneys.
Your bladder is part of the urinary tract. Urine passes from each kidney into the bladder through a long tube called a ureter. Urine leaves the bladder through a shorter tube (the urethra).
The wall of the bladder has layers of tissue. The inner layer of tissue is also called the lining. As your bladder fills up with urine, the transitional cells on the surface stretch. When you empty your bladder, these cells shrink. The middle layer is muscle tissue. When you empty your bladder, the muscle layer in the bladder wall squeezes the urine out of your body. The outer layer covers the bladder. It has fat, fibrous tissue, and blood vessels.
Cancer begins in cells, the building blocks that make up tissues. Tissues make up the bladder and the other organs of the body.
Normal cells grow and divide to form new cells as the body needs them. When normal cells grow old or get damaged, they die, and new cells take their place.
Sometimes, this process goes wrong. New cells form when the body doesn’t need them, and old or damaged cells don’t die as they should. The buildup of extra cells often forms a mass of tissue called a growth or tumor.
Tumors in the bladder can be benign (not cancer) or malignant (cancer). Benign tumors are not as harmful as malignant tumors:
- are usually not a threat to life
- can be treated or removed and usually don’t grow back
- don’t invade the tissues around them
- don’t spread to other parts of the body
- may be a threat to life
- usually can be removed but can grow back
- can invade and damage nearby tissues and organs (such as the prostate in a man, or the uterus or vagina in a woman)
- can spread to other parts of the body
Bladder cancer cells can spread by breaking away from the original tumor. They can spread through the blood vessels to the liver, lungs, and bones. In addition, bladder cancer cells can spread through lymph vessels to nearby lymph nodes. After spreading, the cancer cells may attach to other tissues and grow to form new tumors that may damage those tissues. See the Staging section for information about bladder cancer that has spread.