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Bladder Cancer Basics

About Bladder Cancer

The bladder is a hollow organ that stores urine. It is made up of different layers that include an inner layer of cells (the lining of the bladder), connective tissue, and muscle.  Most forms of bladder cancer start in the inner layer of cells. It can then spread to the connective tissue and the muscle. The type and success of treatment depend on how far the cancer has spread and the type of bladder cell involved.

The main types of bladder cancer include:

  • Transitional cell carcinoma (also referred to as urothelial carcinoma)
  • Squamous cell carcinoma
  • Adenocarcinoma
  • Small cell carcinoma

    The most common bladder cancer is transitional cell carcinoma, also referred to as urothelial carcinoma. According to the American Cancer Society, 95% of bladder cancers are transitional cell carcinoma.  This type of bladder cancer can remain isolated to the bladder lining (noninvasive), spread to the muscle wall of the bladder, as well as beyond to other organs and lymph nodes (invasive).

    Squamous cell carcinoma and adenocarcinoma of the bladder are less common and usually invasive. Both start in cells that develop in the inner lining of the bladder, due typically to chronic or prolonged irritation, infection or inflammation.  According to the American Cancer Society, in the United States, only about 1% to 2% of bladder cancers are squamous cell carcinomas. Only about 1% of bladder cancers are adenocarcinomas.

    Small cell carcinoma of the bladder is uncommon, less than 1% of bladder cancers, according to the American Cancer Society. It develops in the neuroendocrine cells. This type of bladder cancer usually is treated with chemotherapy similar to that used for small-cell carcinoma of the lung.

    If malignant cancer cells begin in the muscle tissue, they are called sarcomas. This is very rare.

    Learn more about this cancer