Cancer - Bladder

The Bladder The bladder is a hollow, muscular, balloon-like organ that stores urine. It sits in the lower part of the abdomen. Urine consists of water and waste products not needed by the body. The bladder is lined with a membrane which stops the urine being absorbed back into the body. The cells of this membrane are called transitional cells or urothelial cells, and the membrane lining is called the urothelium. The kidneys produce urine, which is carried to the bladder by tubes called ureters. The bladder then stores the urine until it is full enough to empty it through a tube called the urethra, which passes urine from the body. In women, the urethra is a very short tube immediately in front of the vagina (birth canal). In men the tube is longer and passes through the prostate gland and the penis. Bladder Cancer Nearly all cancers of the bladder are found in the urothelium (lining of the bladder). These are called transitional cell cancers. They come in a wide range of forms and can behave in very different ways. A large number of transitional cell cancers grow on the inside lining of the bladder. These are called superficial cancers. There are two types of superficial tumours: carcinoma in situ, which are flat and non-invasive, and papillary, which stick out from the lining like mushrooms. Sometimes transitional cell cancers spread into the wall of the bladder. These are called invasive cancers. Squamous cell carcinomas and adenocarcinomas are less common bladder cancers. These types are likely to spread to deeper layers of the bladder.