The Bladder
The bladder is a hollow organ in the lower pelvis. Its main job is to store urine. Urine is
liquid waste made by the kidneys and then carried to the bladder through tubes called
ureters. The bladder gets bigger as it fills with urine. The wall of the bladder is made up of several layers (see image). When you urinate, the muscles in the wall of the bladder contract, and urine is forced out of the bladder through a tube called the urethra. Together, these organs are called the urinary tract.
Bladder Cancer
Bladder cancer is a disease that occurs when cells in the inner lining of the bladder grow out of control. Bladder cancer occurs when abnormal cells in the bladder develop genetic changes (mutations) that cause them to multiply uncontrollably. Cancer cells also avoid the natural process of dying off. As cancer cells increase, they crowd out and overwhelm normal cells. Over time, the cancer cells may form a tumor in the bladder. Sometimes the cells grow deeper and invade the bladder’s muscle layer. The cancer may even break through the bladder and spread to other parts of the body.
Signs and Symptoms of Bladder Cancer
Symptoms of bladder cancer are more likely to be caused by something other than cancer, including conditions such as a urinary tract infection (UTI), bladder stones, an overactive bladder, or an enlarged prostate (in men). Still, it’s important to be checked by a doctor so that the cause can be found and treated, if needed.
Blood in the urine (hematuria) is the first sign of bladder cancer
changes in bladder habits or bladder irritation
the need to go more often or feeling the need to go right away
pain or burning during urination
having trouble going or having a weak urine stream
having to go many times during the night
Advanced bladder cancer signs and symptoms
bladder cancers that have grown large or have spread to other parts of the body can sometimes cause other symptoms, such as:
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Being unable to urinate
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Lower back pain on one side
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Loss of appetite and weight loss
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Feeling tired or weak
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Swelling in the feet
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Bone pain
Types of Bladder Cancer
Urothelial carcinoma
also known as transitional cell carcinoma (TCC), starts in the urothelial cells that line the inside of the bladder. This is by far the most common type of bladder cancer. If you have bladder cancer, it's very likely to be an urothelial carcinoma. Urothelial cells also line the inside of other parts of the urinary tract, such as the part of
the kidney that connects to the ureter (called the renal pelvis), the ureters, and the urethra. People with bladder cancer sometimes have tumors in these places, too, so all the urinary tract needs to be checked for tumors.
Different subtypes of urothelial carcinoma are based on how the cancer cells look under a microscope. Most often, the subtype doesn’t affect how the cancer is treated, although some subtypes might be more likely to have gene changes that could affect treatment options.
Urothelial carcinoma with Divergent differentiation
Sometimes urothelial cancers contain minimal areas that look like some of the other cancer types below. This is known as divergent differentiation. For example, the cancer may contain areas of squamous or glandular differentiation. Most often, this doesn’t affect treatment options.​
Other Types of Bladder Cancer
Other types of cancer can occur in the bladder, but these are much less common than urothelial (transitional cell) cancer.
squamous cell carcinoma
In the US, only about 3% - 5% of bladder cancers are squamous cell carcinomas (SCCs). Seen with a microscope, the cells look much like the flat cells that are found on the surface of the skin.
adinocarcinoma
Only about 1%-2% of bladder cancers are adinocarcinomas. these cancers start in gland forming cells.
small cell carcinoma
Less than 1% of bladder cancers are small cell carcinomas. These cancers start in nerve-like cells called neuroendocrine cells. These cancers often grow quickly and usually need to be treated with chemotherapy like that used for small cell lung cancer.
sarcoma
Sarcomas are cancers that start in connective tissues in the body. In the bladder, sarcomas can start in the muscle cells of the bladder, although these cancers are very rare.