Types & Stages

Bladder Cancer: Types & Stages

Several types of cancer can start in the bladder

Urothelial carcinoma (transitional cell carcinoma)

Urothelial carcinoma, also known as transitional cell carcinoma (TCC), is by far the most common type of bladder cancer. In fact, if you are told you have bladder cancer it is almost certain to be a urothelial carcinoma. These cancers start in the urothelial cells that line the inside of the bladder.

Urothelial cells also line 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. Patients with bladder cancer sometimes have other tumors in these places, so the entire urinary tract needs to be checked for tumors.

Invasive versus non­invasive bladder cancer

Bladder cancers are often described based on how far they have invaded into the wall of the bladder:

  • Non-­invasive cancers are still in the inner layer of cells (the transitional epithelium) but have not grown into the deeper layers.
  • Invasive cancers have grown into deeper layers of the bladder wall. These cancers are more likely to spread and are harder to treat.

A bladder cancer can also be described as superficial or non­muscle invasive. These terms include both non­invasive tumors as well as any invasive tumors that have not grown into the main muscle layer of the bladder.

Papillary versus flat cancer

Bladder cancers are also divided into 2 subtypes, papillary and flat, based on how they grow (see image above).

  • Papillary carcinomasgrow in slender, finger­like projections from the inner surface of the bladder toward the hollow center. Papillary tumors often grow toward the center of the bladder without growing into the deeper bladder layers. These tumors are called non­invasive papillary cancers. Very low­grade (slow growing), non­invasive papillary cancer is sometimes called papillary urothelial neoplasm of low­malignant potential (PUNLMP) and tends to have a very good outcome.
  • Flat carcinomasdo not grow toward the hollow part of the bladder at all. If a flat tumor is only in the inner layer of bladder cells, it is known as a non­invasive flat carcinoma or a flat carcinoma in situ (CIS).

If either a papillary or flat tumor grows into deeper layers of the bladder, it is called an invasive urothelial (or transitional cell) carcinoma.