Bladder and other urothelial cancers are diseases in which malignant (cancer) cells form in the urothelium.

The bladder is a hollow organ in the lower part of the abdomen. It is shaped like a small balloon and has a muscle wall that allows it to get larger or smaller. The bladder holds urine until it is passed out of the body. Urine is the liquid waste that is made by the kidneys as they clean the blood. The urine passes from the two kidneys into the bladder through two tubes called ureters. When the bladder is emptied during urination, the urine goes from the bladder to the outside of the body through another tube called the urethra.

The urothelium is a layer of tissue that lines the urethra, bladder, ureters, prostate, and renal pelvis. Cancer that begins in the urothelium of the bladder is much more common than cancer that begins in the urothelium of the urethra, ureters, prostate, or renal pelvis. Because it is the most common form of urothelial cancer, bladder cancer is the focus of this summary.

There are 3 types of cancer that begin in the urothelial cells of the bladder. These cancers are named for the type of cells that become malignant (cancerous):

• Transitional cell carcinoma: Cancer that begins in cells in the innermost layer of the bladder urothelium. These cells are able to stretch when the bladder is full and shrink when it is emptied. Most bladder cancers begin in the transitional cells.
• Squamous cell carcinoma: Cancer that forms in squamous cells, which are thin, flat cells that may form in the bladder urothelium after long-term infection or irritation.
• Adenocarcinoma: Cancer that begins in glandular (secretory) cells. Glandular cells in the bladder urothelium make substances such as mucus.

Most newly diagnosed bladder cancers occur in people 60 years and older.

In the United States, bladder cancer occurs more often in men than in women, and more often in whites than in blacks. As the U.S. population has gotten older, the number of people diagnosed with bladder cancer has increased, but the number of deaths from bladder cancer has decreased. This is true for men and women of all races over the last 30 years. However, blacks and women with bladder cancer are more likely to die from the disease than white men with bladder cancer are.

Smoking, gender, and diet can affect the risk of developing bladder cancer.

Anything that increases your chance of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. People who think they may be at risk should discuss this with their doctor. Risk factors for bladder cancer include:

• Using tobacco, especially smoking cigarettes.
• Being 60 years or older, male, or white.
• Being exposed to certain substances, such as soot from coal, or chemicals used to make rubber, certain dyes, or textiles.
• Working as a dry cleaner or in places where paper, rope, twine, or clothing is made.
• Taking A. fangchi, a Chinese herb.
• Drinking water that has high levels of arsenic.
• Having a history of many bladder infections.
• Long-term use of urinary catheters.
• Past treatment with certain anticancer drugs or radiation therapy to the pelvis.
• Having a kidney transplant.
• Having an inherited disorder called hereditary nonpolyposis colon cancer (HNPCC; Lynch syndrome).