Doctors usually describe and treat bladder cancer by how far it has grown into the bladder wall.

• NMIBC (non-muscle invasive bladder cancer) is cancer that remains in the urothelial cells that line the bladder.

• MIBC (muscle-invasive bladder cancer) is cancer that has grown into the deeper layers of bladder muscle.

• If bladder cancer has spread to other parts of the body outside the urinary tract, it is advanced disease, or metastatic.

Types of bladder cancer include urothelial carcinoma, squamous cell carcinoma, adenocarcinoma, small cell carcinoma and sarcoma.

Urothelial carcinoma, the most common type of bladder cancer, is also known as transitional cell carcinoma. Transitional cell carcinoma begins in the part of the kidney, called the renal pelvis, where urine collects before moving to the bladder.

Squamous cell carcinoma comprises 1% to 2% of bladder cancers, according to the American Cancer Society. Most squamous cell carcinomas of the bladder are invasive.

Adenocarcinoma, which are also mostly invasive, occur in only 1% of bladder cancers.

Small cell carcinoma, which occurs in less than 1% of bladder cancers, start in the neuroendocrine cells. This subtype of the disease can grow quickly.

Sarcoma of the bladder is rare, and start in the muscle cells of the organ.