Bladder cancer begins when cells in the inner lining of the bladder (urothelium) become abnormal. This causes the cells to grow and divide out of control. As the cancer grows, it may start to spread into the deeper layers of the bladder wall. Some cancer cells can also break off and travel outside the bladder to other parts of the body (e.g. lymph nodes, lungs, bones or liver).
Learn more about:
Types of bladder cancer
There are 3 main types of bladder cancer. They are named after the cells they start in.
| urothelial carcinoma |
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| squamous cell carcinoma |
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| adenocarcinoma |
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There are also rarer types of bladder cancer. These include sarcomas, which start in the muscle, and an aggressive form called small cell carcinoma.
Urothelial carcinoma occasionally starts in a ureter or part of a kidney. This is known as upper tract urothelial cancer. For information about how this cancer is diagnosed and treated, see Upper tract urothelial cancer.
The bladder
The bladder is a hollow, muscular sac that stores urine (wee or pee). It sits behind the pubic bone in the pelvis, and is part of the urinary system.
The urinary system also includes 2 kidneys, 2 tubes called ureters that lead from the kidneys into the bladder, and another tube called the urethra that leads out of the bladder. In males, the urethra is a long tube that passes through the prostate and down the penis. In females, the urethra is shorter and opens in front of the vagina (birth canal).
The kidneys produce urine, which travels to the bladder through the ureters. The bladder is like a balloon and expands as it fills with urine. A layer of muscle wraps around the urethra and works like a valve to keep the bladder closed and stop leaking of urine. When you are ready to empty your bladder, the bladder muscle tightens and the valves open, and urine passes through the urethra and out of the body.
Layers of the bladder wall
There are 4 main layers of tissue in the bladder:
| urothelium | The inner layer. It is lined with cells called urothelial cells that stop urine being absorbed into the body. |
| lamina propria | A layer of tissue and blood vessels that surrounds the urothelium. |
| muscularis propria | The thickest layer. It consists of muscle that tightens to empty the bladder. |
| perivesical tissue | The outer layer. Mostly made up of fatty tissue, it separates the bladder from nearby organs. |
The urinary system
*Reproductive organ, not part of urinary system
Who gets bladder cancer?
Each year, about 3100 Australians are diagnosed with bladder cancer. Most people diagnosed with bladder cancer are aged 60 or older, but it can occur at any age.
About 1 in every 140 males will be diagnosed with bladder cancer before age 75, making it 1 of the 10 most common cancers in males. For females, the risk is about 1 in 560, although it is often diagnosed at an advanced stage.
What causes bladder cancer?
Research shows that people with certain risk factors are more likely to develop bladder cancer.
Risk factors include:
| Smoking | People who smoke are up to 3 times more likely than non-smokers to develop bladder cancer. |
| Older age | About 90% of people diagnosed with bladder cancer in Australia are aged over 60. |
| Being male | Men are about 3 times more likely than women to develop bladder cancer. |
| Chemical exposure at work | Chemicals called aromatic amines, benzene products and aniline dyes are linked to bladder cancer. These chemicals are used in rubber and plastics manufacturing, in the dye industry, and sometimes in the work of painters, machinists, printers, hairdressers, firefighters and truck drivers. |
| Parasitic bladder infections | One of the rarer types of bladder cancer (squamous cell carcinoma of the bladder) has been linked to a parasitic bladder infection called schistosomiasis. This is very rare in people born in Australia; it is caused by a parasite found in fresh water in Africa, Asia, South America and the Caribbean. |
| Long-term catheter use | Using urinary catheters over a long period may be linked with squamous cell carcinoma of the bladder. |
| Previous cancer treatments | These include the chemotherapy drug cyclophosphamide and radiation therapy to the pelvic area. |
| Diabetes treatment | The diabetes drug pioglitazone can increase the risk of bladder cancer. |
| Personal or family history | Most people with bladder cancer do not have a family history. However, having one or more close blood relatives diagnosed with bladder cancer, or having inherited a gene linked to bladder cancer, slightly increases the risk of bladder cancer. |
→ READ MORE: Bladder cancer symptoms
More resources
Dr Prassannah Satasivam, Urologist and Robotic Surgeon, Epworth Hospitals and Cabrini Hospitals, VIC; Donna Clifford, Urology Nurse Practitioner, Royal Adelaide Hospital, SA; Marc Diocera, Genitourinary Nurse Consultant, Peter MacCallum Cancer Centre, VIC; Dr Renee Finnigan, Radiation Oncologist, Gold Coast University Hospital, QLD; Lisa Hann, 13 11 20 Consultant, Cancer Council SA; Dr Andrew Hirschhorn, Director of Allied Health and MQ Health Academy, MQ Health, Macquarie University, NSW; Anne Marie Lyons, Stomal Therapy Nurse, Concord Hospital and NSW Stoma Limited, NSW; John McDonald, Consumer; Prof Manish Patel, Urological Cancer and Robotic Surgeon, Westmead Hospital, Macquarie University Hospital, and The University of Sydney, NSW; Dr Jason Paterdis, Urological Surgeon, Brisbane Urology Clinic, QLD; Graeme Sissing, Consumer; Prof Martin Stockler, Medical Oncologist, The University of Sydney, Concord Cancer Centre, and Chris O’Brien Lifehouse RPA, NSW.
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