Bladder Cancer: What is it?
Bladder tumors are grouped by the way the cancer cells look under a microscope. The type of bladder cancer you have can affect your treatment options because different types respond to different treatments.
People with bladder cancer sometimes have a similar tumor in the lining of another part of the urinary system. So, when someone is found to have cancer in one part of their urinary system, the whole urinary tract needs to be checked for tumors.
Transitional cell carcinoma: This is by far the most common type of bladder cancer. It starts in the cells that line the inside of the bladder – the urothelial cells. It is also called urothelial carcinoma.
Within this group there are subtypes. Papillary cancers grow like fingers from the inner bladder lining toward its hollow center, while flat cancers do not grow toward the center.
These tumors are also named based on whether they tend to spread and invade other organs. If they grow deeper into the bladder wall they are called invasive; if not, they are non-invasive.
These tumors are divided into grades based on how the cells look under the microscope. If the cells look more like normal cells, the cancer is called a low-grade cancer. When the cells look very different from normal, the cancer is high-grade. Lower-grade cancers tend to grow more slowly and have a better outcome than higher-grade cancers.
Squamous cell carcinoma: This type is much less common and is usually invasive.
Adenocarcinoma: This type is also much less common and almost all are invasive.
Small-cell carcinoma: A very small number of bladder cancers are of this type.
While there are other types of bladder cancer, they are very rare. Ask your doctor to explain to you exactly what type of tumor you have and what it means in your case.
*Information from the American Cancer Society.