Most bladder cancers start with mutations that occur in the cells that line the bladder. These are called transitional cells, and this type of cancer is transitional cell cancer.

Bladder cancer is best thought of in three ways:

• Superficial bladder cancer involves the lining of the bladder.
• Invasive bladder cancer means the cancer has spread to the muscular wall that makes up much of the bladder.
• Metastatic bladder cancer occurs when the cancer has spread to either the lymph nodes that surround the bladder or into other organs of the pelvis or abdomen or the lungs.

The three types are treated differently:

• For superficial bladder cancer, the urologist removes the tumors using a cystoscope. During the procedure, the doctor may instill medication into the bladder to decrease the risk of recurring cancer. The medication may be chemotherapy (so called intravesical chemotherapy) or an immune-stimulating agent, such as BCG. The bladder is periodically checked to make sure the cancer has not returned.
• Invasive bladder cancer is generally treated by removing the bladder and replacing it with an artificial bladder, generally made out of the patient's intestine. Sometimes, chemotherapy is used. Doctors are studying whether radiation therapy can effectively treat invasive cancer that has spread into the muscle layer.
• Metastatic bladder cancer, which has spread to the lymph nodes or to the liver or other organs, is generally treated with chemotherapy taken by mouth or given intravenously. The treatment is usually given over several months.