The Start and Spread of Urothelial Bladder Cancer

Almost 20,000 women in the U.S. get urothelial bladder cancer (UBC) each year. 

The Four Layers Layers of the Bladder Wall

• Urothelial/Transitional epithelium

• Lamina propria

• Detrusor muscle

• Fatty connective tissues

Most types of UBC start in the cells that line the innermost layer of the bladder, called the urothelium. 

Muscle invasive bladder cancer (MIBC)

• Has spread to muscle layer of the bladder wall

• Is more advanced

• Is more likely to spread

• Is harder to treat 

Non-muscle invasive bladder cancer (NMIBC)

• Is usually stage 0 (non-invasive) or stage 1 (early invasive)

• Hasn’t spread to the muscle layer

There are 2 types of NMIBC: 

Non-invasive flat carcinomas 

• Also called carcinoma in situ (CIS)

• Don’t grow toward the hollow part of the bladder

• Hard to spot because they are falter and blend in with the wall

• High risk of spreading or coming back 

Non-invasive papillary carcinomas

• Grow toward the hollow part of the bladder

• Thin and finger-like

• Can spread or come back 

About 1 in 10 patients with bladder cancer present with CIS at diagnosis.

The ureter and urethra also have urothelial cells and can develop urothelial cancer. 

Sometimes cancer spreads to other parts of the body such as lymph nodes, bones, lungs or liver. 

This educational resource was created with support from Merck.