The bladder is a hollow organ in the lower abdomen. It stores urine, the liquid waste produced by the kidneys.
Your bladder is part of the urinary tract. Urine passes from each kidney into the bladder through a tube called a ureter. Urine leaves the bladder through a shorter tube (the urethra).
The wall of the bladder has layers of tissue:
- Inner layer: 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.
- Middle layer: 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.
- Outer layer: 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:
- Benign 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
- Malignant growths:
- 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
When you get a diagnosis of bladder cancer, it’s natural to wonder what may have caused the disease. Doctors can’t always explain why one person gets bladder cancer and another doesn’t.
However, we do know that people with certain risk factors may be more likely than others to develop bladder cancer. A risk factor is something that may increase the chance of getting a disease.
Studies have found the following risk factors for bladder cancer:
- Smoking: Smoking tobacco is the most important risk factor for bladder cancer. Smoking causes most of the cases of bladder cancer. People who smoke for many years have a higher risk than nonsmokers or those who smoke for a short time.
- Chemicals in the workplace: Some people have a higher risk of bladder cancer because of cancer-causing chemicals in their workplace. Workers in the dye, rubber, chemical, metal, textile, and leather industries may be at risk of bladder cancer. Also at risk are hairdressers, machinists, printers, painters, and truck drivers.
- Personal history of bladder cancer: People who have had bladder cancer have an increased risk of getting the disease again.
- Certain cancer treatments: People with cancer who have been treated with certain drugs (such as cyclophosphamide) may be at increased risk of bladder cancer. Also, people who have had radiation therapy to the abdomen or pelvis may be at increased risk.
- Arsenic: Arsenic is a poison that increases the risk of bladder cancer. In some areas of the world, arsenic may be found at high levels in drinking water. However, the United States has safety measures limiting the arsenic level in public drinking water.
- Family history of bladder cancer: People with family members who have bladder cancer have a slightly increased risk of the disease.
Many people who get bladder cancer have none of these risk factors, and many people who have known risk factors don’t develop the disease.
Bladder cancer may cause these common symptoms:
- Finding blood in your urine (which may make the urine look rusty or darker red)
- Feeling an urgent need to empty your bladder
- Having to empty your bladder more often than you used to
- Feeling the need to empty your bladder without results
- Needing to strain (bear down) when you empty your bladder
- Feeling pain when you empty your bladder
These symptoms may be caused by bladder cancer or by other health problems, such as an infection. People with these symptoms should tell their doctor so that problems can be diagnosed and treated as early as possible.