Bladder cancer is an abnormal growth of abnormal cells in the bladder, the balloon-shaped organ that stores urine.
Bladder cancer begins in the lining of the bladder. In 70 and 80% of people with bladder cancer, the cancer is discovered when a problem is still limited and superficial. These cancers usually appear superficial bladder as a patch of abnormal cells isolated on the mucosa of the bladder as a bulge or odd, with the form of a finger along the inner wall of the bladder. Less frequently, the tumor is diagnosed when it is invasive, which means that the tumor has invaded deeply into the muscle of the bladder wall, has spread (metastasized) to lymph nodes or has spread around to other organs.
There are three classes of bladder cancer, which have different types of cells. About 90% of bladder cancers are transitional cell carcinomas. The rest are squamous cell carcinomas (6 to 8%) or adenocarcinomas (2%).
Little is known about the causes of bladder cancer. It is believed that the majority of transitional cell carcinomas are caused by carcinogens (substances that cause cancer), snuff as smoke and chemicals in the environment. Smokers get cancer two to four times more often than those who do not smoke, but about half of patients with bladder cancer have never smoked. Bladder cancer is also associated with exposure to certain industrial chemicals, but exposure to such chemicals has been greatly reduced thanks to new safety laws in the workplace. These include industrial carcinogens such as aniline dyes, polycyclic aromatic hydrocarbons (such as 2-naphthylamine, 4-aminobiphenyl or benzidine), polychlorinated biphenyls or chemicals used to manufacture aluminum. These chemicals are used in the aluminum, rubber, chemical and leather, as well as dry cleaners, chimney sweeps, hairdressers, painters, printers, textile workers, machinists and truck drivers. In developing countries, a parasitic disease called schistosomiasis increases the risk of developing bladder cancer.
Bladder cancer tends to return in people who have this disease. After the cancer is treated, there is much chance of other cancers that develop in other areas, either within the same bladder, the ureters (the tubes that drain urine from the kidneys to the bladder) or part the kidney called the renal pelvis. The risk of other cancers develop somewhere in the urinary tract means that once you have had bladder cancer, will need frequent checkups.
In the United States, bladder cancer is the fourth most common cancer among men and the ninth most common in women. About 63,000 new cases are diagnosed each year, mostly in adults over 55 years. Caucasians are twice as likely to develop bladder cancer than African Americans and three times more likely that the disease affects men than women. Bladder cancer kills about 13,000 Americans each year.