Understanding bladder cancer - basics

What is bladder cancer?

The bladder is a pouch in your urinary tract that stores urine after it is produced by the kidneys. The bladder is lined with specialised cells called transitional cells.

Bladder cancer can arise from these transitional cells. The cancer spreads by penetrating bladder muscle, infiltrating surrounding fat and tissue, and - if untreated - eventually spreading to other organs and tissues in the body, such as the lungs, liver or bones.

The earlier the cancer is diagnosed, the more limited it will likely be and the more effective the treatment. Thanks to improved procedures for early detection and treatment, five-year survival rates for bladder cancer improved from 50 per cent in the 1960s to over 70 per cent in the 1990s. Although bladder cancers often recur, prompt diagnosis means they can be treated while they are still superficial.

According to Cancer Research UK, there were around 10,090 new cases of bladder cancer in the UK in 2007. The most common site of tumours in the urinary system is the bladder, and bladder cancer is the seventh most common cancer in the UK.

It also is the fourth most common cancer in UK males, with over 7,300 new cases diagnosed each year in the UK, Cancer Research UK says. This compares with almost 3,000 new cases in women each year in the UK, making it more than twice as common in men than in women. 

Few cases of bladder cancer are reported under the age of 50, but then the rates rise steeply to peak in UK males at 75 to 79 years (age at diagnosis), when the incidence is around three times that in women of the same age.

Many bladder tumours are not cancerous. Make sure you talk to your doctor to understand what type of bladder tumour you may have.

What causes bladder cancer?

We do not know the exact cause of bladder cancer. But there are a number of risk factors linked to the disease.

Bladder irritation. Chronic irritation of the bladder increases the risk of cancer. So people with birth defects affecting the bladder, chronic bladder (urinary) infections or persistent cystitis - inflammation of the bladder - are more susceptible, as are people with histories of benign bladder tumours. Also, kidney and bladder stones have been linked to bladder cancer.

Smoking and other chemical exposure. More than most cancers, bladder cancer is associated with exposure to cancer-promoting chemicals, or carcinogens. For example, cigarette smokers have double the risk of developing bladder cancer compared with non-smokers, because of specific carcinogens in tobacco smoke. People exposed to certain chemicals and dyes, such as painters, leather workers, machinists, metal workers, and rubber and textile workers, are at increased risk of bladder cancer. People who have been treated with radiation or alkylating chemotherapy agents, such as cyclophosphamide, are also at higher risk.

Consumption of nitrates in smoked and cured meats may also be associated with bladder cancer, as may consumption of caffeine and saccharine. However, the connection is so weak that some researchers question the risk at all.

Chemotherapy. Some medications used to treat other cancers can increase the risk of bladder cancer.

Use of the herb, Aristolochia fangchi . This Chinese herb, taken by some people to help them lose weight, has been linked to bladder cancer. Traditional Chinese medicines containing aristolochia extracts are officially banned in the UK.