What are the causes and risk factors for bladder cancer?
The risk factors for bladder cancer are numerous. Some of these factors are directly related to an individual's constitution (constitutional factors), while others are linked to the environment (environmental factors). It is the interaction between constitutional and environmental factors that leads to the development of bladder cancer.
Environmental factors
Several environmental factors increase the risk of bladder cancer. The most significant is tobacco use, which is the primary risk factor for bladder cancer (source: cancer-environnement.fr).
More than half of bladder cancers are directly or indirectly attributable to smoking. Smokers have a risk of developing bladder cancer that is two to six times higher than that of non-smokers. The risk increases proportionally with the daily consumption of cigarettes and the duration of smoking. However, the risk decreases after quitting smoking, and after 15 years, the risk for a former smoker is similar to that of a non-smoker.
Other factors, such as exposure to arsenic and opium, also increase the risk of bladder cancer. Previous chemotherapy with drugs like cyclophosphamide or ifosfamide increases this risk as well, making it important for patients treated with these chemotherapies to drink plenty of fluids to limit the risk.
Prior radiotherapy to the abdomen or pelvis also increases the risk. Chronic bladder irritation caused by inflammation, injury, or an infection like schistosomiasis—caused by the parasite Schistosoma haematobium—also raises the risk of bladder cancer. Notably, occupational exposure to certain chemicals significantly increases the risk.
This is true for people working in industries such as textiles (with certain dyes), leather, dye manufacturing, rubber production, steel, aluminum, the chemical or pharmaceutical industry, chimney sweeping and boiler maintenance, painting, and hairdressing, especially those who used certain hair dyes before the 1980’s, which are now banned.
Constitutional factors
Among constitutional factors, as with most cancers, age is a significant risk factor. More than half of the cases are diagnosed between the ages of 50 and 80. 85% of men and 89% of women with bladder cancer are over 60 years old (source: cancer-environnement.fr).
Gender is another risk factor: men are more likely than women to develop bladder cancer.
Among other constitutional factors, heredity can play a role. These hereditary forms are due to genetic mutations passed down from one generation to the next, which are involved in cancer development.
💡 DID YOU KNOW ?
DNA is made up of 3 billion molecules contained within the nuclei of the 30 trillion cells that make up our bodies. This DNA consists of a sequence of four different elements, named A, T, G, or C after the first letter of their full names. It forms a double helix and holds all the information necessary for the functioning of each cell. This information is contained in small fragments of DNA called " genes ".
There are approximately 21,000 genes that determine how a cell functions and the production of proteins, which are essential components of cells.
Mutations can occur in the DNA, changing one element to another within one or more genes. These mutations can be passed from a parent to a child ( hereditary genetic mutations ) or arise spontaneously in an individual during their lifetime ( sporadic mutations ). Some mutations can increase the risk of developing cancer.
A genetic predisposition to bladder cancer is primarily observed in patients with Lynch syndrome.
Expert perspective
Lynch syndrome is a genetic disorder that primarily affects the colon-rectum and endometrium. Patients with Lynch syndrome have a higher risk of developing colorectal cancer, typically around the age of 45. They also have an increased risk of developing cancers of the endometrium, ovaries, stomach, small intestine, bile ducts, or urinary tract. This syndrome is thought to be responsible for about 5% of bladder cancers.1
Additionally, a familial tendency to develop bladder cancer is observed in some individuals. This familial tendency may be due to a genetic predisposition, a shared lifestyle among family members, chance, or a combination of these factors.
If a first-degree relative (father, mother) had bladder cancer before the age of 45, the children are at a higher risk of developing this disease (source: arcagy.org).
Other risk factors are suspected, such as air pollution or certain pesticides. On the other hand, it appears that consuming fruits and vegetables has a protective effect against the development of bladder cancer (source: cancer-environnement.fr).
1 Dyrskjøt, L. et al. Bladder cancer. Nat Rev Dis Primers 9, 58 (2023).
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Article updated on Jan 20, 2025
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