About 67,160 Americans will be diagnosed with bladder cancer this year, according to the American Cancer Society. Bladder cancer is nearly three times more common in men than in women and is most common in people over age 70.
The bladder is an expandable, hollow organ in the pelvis where urine is stored until it is emptied from the body through the urethra. The wall of the bladder has several layers including the surface cells, which expand and deflate (the transitional epithelial cells), smooth muscle, and a fibrous layer. The extent to which the cancer has penetrated these layers influences a patient's treatment and prognosis.
Types of Bladder Cancer
Transitional cell carcinoma (TCC), also known as urothelial carcinoma, is the most common form of bladder cancer and accounts for nearly 90 percent of cases. About 70 percent of TCC cases are noninvasive, meaning that the cancer is confined to the lining of the bladder and is unlikely to spread. The other 30 percent of TCC cases are more advanced. In these patients, either the cancer has penetrated the bladder's lining and grown into the muscular wall of the bladder (called muscle-invasive bladder cancer), or it has spread, or metastasized, to other organs.
Less common bladder cancer types include squamous cell carcinoma, which accounts for about 8 percent of cases, and small cell carcinoma and adenocarcinoma, both of which account for only 1 to 2 percent of bladder cancer cases in the US.
While most cases of bladder cancer in industrialized nations such as the US, Canada, and France are transitional cell carcinomas, in developing countries, 75 percent of cases are squamous cell carcinomas caused by infection with the parasitic organism Schistosoma haematobium.
