Bladder cancer is the growth of malignant cells in the urinary bladder. Most forms of bladder cancer start in the superficial layer of the transitional epithelium, and most often affect the transitional cells. It may also be called transitional cell carcinoma or even urothelial carcinoma. Urothelial carcinoma is also a term used for transitional cell cancer in the renal pelvis, ureters, and urethra.
Bladder cancer is a relatively common disease. It is the fourth leading cancer among men (following prostate, lung, colorectal cancers), and the tenth leading cancer among women; occurring in men about three times more often than women.
Like most types of cancer, bladder cancer usually involves epithelial cells, in this case, the transitional epithelium that lines the urinary bladder. Constant repetitive damage to the epithelium causes the mature cells to die. This stimulates rapid replication in the basal layer, and soon new colonies of immature cells migrate to the surface. These new cells are easily disrupted by genetic mutations and may become malignant growths that cause bleeding into the bladder.
The causes of bladder cancer vary according to medical history and geographical location. People who have had pelvic radiation for other problems and people who have had chronic infections, bladder stones, or catheter use are at an increased risk for developing bladder cancer. In Africa, Asia, and South America, bladder cancer is associated with a specific parasitic infection, called Schistosoma haematobium.
In the United States and industrial countries, most cases of bladder cancer are directly related to more controllable factors. The transitional epithelium of the bladder seems to be particularly susceptible to damage from environmental toxins. Several genetic mutations that limit the body’s ability to slow down tumor growth or invasion have been linked to bladder cancer. These mutations are frequently triggered by exposure to...