Incidence and Mortality
Bladder cancer is the sixth most common cancer in the United States after lung cancer, prostate cancer, breast cancer, colon cancer, and lymphoma. It is the third most common cancer in men but only the eleventh most common cancer in women. Of the roughly 70,000 new cases annually, about 53,000 are in men and about 18,000 are in women. Of the roughly 15,000 annual deaths, over 10,000 are in men and fewer than 5,000 are in women. The reasons for this disparity between the sexes are not well understood.
Estimated new cases and deaths from bladder cancer in the United States in 2014:
- New cases: 74,690.
- Deaths: 15,580.
The urinary tract consists of the kidneys, the ureters, the bladder, and the urethra. The urinary tract is lined with transitional cell urothelium from the renal pelvis to the proximal urethra. Transitional cell carcinoma (also referred to as urothelial carcinoma) can develop anywhere along this pathway.
Anatomy of the male urinary system (left panel) and female urinary system (right panel) showing the kidneys, ureters, bladder, and urethra. Urine is made in the renal tubules and collects in the renal pelvis of each kidney. The urine flows from the kidneys through the ureters to the bladder. The urine is stored in the bladder until it leaves the body through the urethra.
Under normal conditions, the bladder, the lower part of the kidneys (the renal pelvises), the ureters, and the proximal urethra are lined with a specialized mucous membrane referred to as transitional epithelium (also called urothelium). Most cancers that form in the bladder, the renal pelvises, the ureters, and the proximal urethra are transitional cell carcinomas (also called urothelial carcinomas) that derive from transitional epithelium. (Refer to the PDQ summaries on Renal Cell Cancer Treatment and Transitional Cell Cancer of the Renal Pelvis and Ureter Treatment for more information.)
Transitional cell carcinoma of the bladder can be low-grade or high-grade:
Low-grade bladder cancer often recurs in the bladder after treatment but rarely invades the muscular wall of the bladder or spreads to other parts of the body. Patients rarely die from low-grade bladder cancer.
High-grade bladder cancer commonly recurs in the bladder and also has a strong tendency to invade the muscular wall of the bladder and spread to other parts of the body. High-grade bladder cancer is treated more aggressively than low-grade bladder cancer and is much more likely to result in death. Almost all deaths from bladder cancer are due to high-grade disease.