The bladder is a hollow organ with a muscular wall, located in the pelvis. It is part of the urinary system, which produces, stores and gets rid of liquid waste (urine). The urinary system also includes two kidneys, two ureters and the urethra.
The kidneys produce urine, which travels to the bladder through tubes called ureters. The bladder is like a balloon and inflates as it fills. When it is full, the bladder muscle contracts and urine is passed through a tube called the urethra and out of the body.
In women, the urethra is a short tube that opens in front of the birth canal (vagina). In men, the tube is longer and passes through the prostate and down the penis.
There are three main layers of tissue in the bladder:
Bladder cancer occurs when cells in the bladder become abnormal, which causes them to grow and divide out of control.
The cancer may be categorised according to how far it has spread into the layers of the bladder.
The cancer cells are found only in the inner lining of the bladder (urothelium) and haven’t grown into the deeper layers of the bladder wall. One type of non-invasive cancer is carcinoma in-situ. Most bladder cancers are non-invasive.
The cancer has spread beyond the lining of the bladder (urothelium) into the muscle wall, either into the lamina propria or the muscle, or right through the bladder wall.
Although fast-growing (high-grade) non-invasive tumours, such as carcinoma in-situ, are confined to the original site in the bladder lining, they can grow quickly and become invasive. If you have this type of non-invasive cancer, you will need immediate, and sometimes aggressive, treatment. For more details, see staging and grading.
There are three main types of bladder cancer. They are named after the cell type in which the cancer first develops.
About 90% of all bladder cancers start from the innermost urothelial layer of the bladder wall. This used to be called transitional cell carcinoma.
Urothelial cancer is divided into two subgroups depending on its shape and how it grows. Papillary urothelial carcinoma has slender, finger-like projections and grows towards the hollow centre of the bladder. Flat urothelial carcinoma, such as carcinoma in-situ, does not grow towards the hollow part of the bladder.
Accounts for about 8% of all bladder cancers. This type of cancer starts in the thin, flat cells lining the bladder. It is more likely to be invasive.
The rarest type of bladder cancer, making up 1–2% of all cases. This cancer develops from the cells that produce mucus and is likely to be invasive.
Each year, more than 2400 Australians are diagnosed with bladder cancer. Most people diagnosed with bladder cancer are 60 or older. Men are about three times more likely than women to be diagnosed with bladder cancer.
Sometimes bladder cancer doesn’t have many symptoms and is found during routine urine tests.
This is the most common symptom of bladder cancer. It often occurs suddenly, but is usually not painful. There may only be a small amount of blood in the urine and it may look red or brown. For some people, the blood may come and go, or it may only appear once or twice.
Never ignore blood in your urine. Even if you’ve only noticed blood in the urine once, and it is painless, see your doctor.
A burning feeling when passing urine, needing to pass urine more often or urgently, not being able to urinate when you feel the urge and pain during urination can also be symptoms.
Less commonly, people have pain in one side of their lower abdomen or back.
If you have any of these symptoms or are concerned, see your doctor as soon as possible. Blood in your urine can also be caused by kidney or bladder stones, and non-cancerous enlargement of the prostate in men. Some of these symptoms may indicate that you have bladder irritation or an infection.
Research shows that people with certain risk factors are more likely to develop bladder cancer. These include:
Reviewed by: Dr Mohan Arianayagam, FRACS (Urol), Urologic Oncologist, Nepean Hospital, Penrith, NSW; Donna Clifford, Urology Nurse Practitioner Candidate, Royal Adelaide Hospital, SA and David Connah, Cancer Council Connect Consumer Volunteer.