The bladder is a hollow organ in the lower abdomen. It stores urine, the liquid waste produced by the kidneys. Urine passes through the urinary system, from each kidney into the bladder through a tube called a ureter.
An outer layer of muscle surrounds the inner lining of the bladder. When the bladder is full, the muscles in the bladder wall can tighten to allow urination. Urine leaves the bladder through another tube, the urethra. Bladder cancer is a disease in which malignant cancer cells form in the tissues of the bladder.
Bladder Cancer: Who's at Risk?
No one knows the exact causes of bladder cancer. People who get bladder cancer are more likely than other people to have certain risk factors. A risk factor is something that increases a person's chance of developing the disease. Still, most people with known risk factors do not get bladder cancer, and many who do get this disease have none of these factors. Doctors can seldom explain why one person gets this cancer and another does not. Studies have found the following risk factors for bladder cancer:
- Age. The chance of getting bladder cancer goes up as people get older. People under 40 rarely get this disease.
- Tobacco. The use of tobacco is a major risk factor. Cigarette smokers are two to three times more likely than nonsmokers to get bladder cancer. Pipe and cigar smokers are also at increased risk.
- Occupation. Some workers have a higher risk of getting bladder cancer because of carcinogens in the workplace. Workers in the rubber, chemical, and leather industries are at risk. So are hairdressers, machinists, metal workers, printers, painters, textile workers, and truck drivers.
- Infections. Being infected with certain parasites increases the risk of bladder cancer. These parasites are common in tropical areas but not in the United States.
- Treatment with cyclophosphamide or arsenic. These drugs are used to treat cancer and some other conditions. They raise the risk of bladder cancer.
- Race. Whites get bladder cancer twice as often as African Americans and Hispanics. The lowest rates are among Asians.
- Being a man. Men are two to three times more likely than women to get bladder cancer.
- Family history. People with family members who have bladder cancer are more likely to get the disease. Researchers are studying changes in certain genes that may increase the risk of bladder cancer.
- Personal history of bladder cancer. People who have had bladder cancer have an increased chance of getting the disease again.