Risks & Causes of Bladder Cancer

Find out what causes bladder cancer and how you can reduce your risk.

How common is bladder cancer

Around 440 people are diagnosed with bladder cancer each year in Ireland. It is the 9th most common cancer in the country (not counting non melanoma skin cancer). It is the 8th most common cancer in men.

Who gets it

Bladder cancer usually takes a long time to develop, so it is most common in older people. 3 in 4 people (over 75%) who get bladder cancer in Ireland are 65 years or older. It is rarer in people under 50, but it is important for all age groups to remain vigilant.

More men than women get bladder cancer. This may just be because more men than women have smoked or been exposed to chemicals/dyes at work in recent decades.

We don’t know what causes most bladder cancers. But some factors may increase your risk of getting it.

Smoking and bladder cancer

Smoking cigarettes definitely increases the risk of bladder cancer. Over a third of all bladder cancers are caused by smoking.

Your risk of getting bladder cancer if you smoke is up to 4 times that of someone who has never smoked. People with the highest risk are those who:

  • smoke heavily
  • started smoking at a young age
  • have smoked for a long time

Smoking cigars and pipes also increases your risk.

If you or someone you know smokes and would like help quitting, FREEPHONE 1800 201 203 or FREETEXT QUIT TO 50100, or visit www.quit.ie to get free support and advice from the HSE.

Workplace exposures

Certain industrial chemicals have been linked with bladder cancer. Chemicals called aromatic amines, such as benzidine and beta-naphthylamine, which are sometimes used in the dye industry, can cause bladder cancer.

Workers in other industries that use certain organic chemicals also may have a higher risk of bladder cancer. Industries carrying higher risks include makers of rubber, leather, textiles, and paint products as well as printing companies. Other workers with an increased risk of developing bladder cancer include painters, machinists, printers, hairdressers (probably because of heavy exposure to hair dyes), and truck drivers (likely because of exposure to diesel fumes).

If you have been diagnosed with bladder cancer, It is worth finding out if you have ever been exposed to a chemical mentioned here. If you have, talk to your urologist or cancer doctor.

Arylamines

A group of chemicals called arylamines are known to cause bladder cancer. Some of these chemicals have now been banned but you may have been exposed to them if you work in industries such as rubber or plastics manufacture. It can take up to 25 years for a bladder cancer to develop.

Arylamines that increase risk of bladder cancer include:

  • aniline dyes
  • 2-Naphthylamine
  • 4-Aminobiphenyl
  • xenylamine
  • benzidine
  • o-Toluidine

Polycyclic aromatic hydrocarbons

A group of chemicals called polycyclic aromatic hydrocarbons (PAHs) increase the risk of bladder cancer. You may have been exposed to them if you have worked in:

  • industries where people handle carbon or crude oil, or substances made from them
  • any industry involving combustion, such as smelting.

Chlorine and trihalomethanes

Chlorine is used to disinfect drinking water and swimming pools. It breaks down into chemicals called trihalomethanes (THMs) that stop harmful bacteria from growing. Researchers have looked at whether exposure to THMs by drinking chlorinated water can increase bladder cancer risk.

Some research studies seem to show that long term drinking of tap water with high levels of THMs may increase the risk of bladder cancer. But findings are mixed.It is important to remember that disinfecting water reduces the risk of serious infectious diseases. So the overall risk of not chlorinating water is likely to be higher than the overall risk of being exposed to THMs.

Risk factors you cannot change

Race and ethnicity- Whites are about twice as likely to develop bladder cancer as African Americans and Hispanics. Asian Americans and American Indians have slightly lower rates of bladder cancer. The reasons for these differences are not well understood.
Age – Bladder cancer usually takes a long time to develop, so it is most common in older people. 3 in 4 people (over 75%) who get bladder cancer in Ireland are 65 years or older. It is rarer in people under 50.

Gender – Bladder cancer is much more common in men than in women.

Chronic bladder irritation and infections –  Urinary infections, kidney and bladder stones, bladder catheters left in place a long time, and other causes of chronic bladder irritation have been linked with bladder cancer (especially squamous cell carcinoma of the bladder), but it’s not clear if they actually cause bladder cancer.

Personal history of bladder or other urothelial cancer – Having a cancer in the lining of any part of the urinary tract puts you at higher risk of having another cancer, either in the same area as before, or in another part of the urinary tract. This is true even when the first tumor is removed completely. For this reason, people who have had bladder cancer need careful follow-up to look for new cancers, particularly in the urinary tract.

Genetics and family history – People who have family members with bladder cancer have a higher risk of getting it themselves. Sometimes this may be because the family members are exposed to the same cancer-causing chemicals (such as those in tobacco smoke). They may also share changes in some genes (like GST and NAT) that make it hard for their bodies to break down certain toxins, which can put them at further risk of bladder cancer.

Prior chemotherapy or radiation therapy -Taking the chemotherapy drug cyclophosphamide (Cytoxan) for a long time can irritate the bladder and increase the risk of bladder cancer. People taking this drug are often told to drink plenty of fluids to help protect the bladder from irritation. People who are treated with radiation to the pelvis are more likely to develop bladder cancer.