There are many risk factors for bladder cancer that are known. In this country, the biggest risk factor for bladder cancer is smoking. Other risk factors include exposure to benzene dyes, recurrent urinary tract infections, long-term indwelling catheters, bladder stones, and pelvic radiation therapy received for treatment of other cancers. Also, the risk of bladder cancer is mildly increased with the use of permanent hair dyes. The risk of bladder cancer is also increased in people who dye their hair frequently or who start dyeing their hair at a young age. Dietary factors can also influence the development of bladder cancer. People who also have other tumors have an increased risk of developing bladder cancer again compared to the general population, and this risk is highest in patients with a prior diagnosis of prostate cancer. Bladder schistosomiasis infection significantly increases the risk of bladder cancer. This infection is common in Egypt and neighboring countries, but rare in the country.
Tobacco: 25-65% of patients with bladder cancer smoke. The risk of bladder cancer is four times higher in smokers compared to never smokers. The risk increases as the number of cigarettes smoked increases, the duration of smoking increases, and it is related to the amount inhaled per occasion, the same for both men and women. Quitting smoking reduces the risk of bladder cancer, so it’s not too late to quit. Other tobaccos such as cigars and smokeless tobacco, although to a lesser extent, can also increase the risk of bladder cancer. It is not clear which substances in tobacco can cause bladder cancer. If the body is slow to clear the chemicals in tobacco, these people, called “slow acetylators,” are at higher risk for bladder cancer.
Occupational factors: Exposure to benzene dyes is the most common industrial risk factor for bladder cancer. Benzene dyes are a byproduct of coal combustion. These fuels are used to dye wool or textiles. Other chemicals associated with bladder cancer include 2-naphthylamine, 4-aminobenzyl, 4-nitrobenzyl, 4-4-diaminobenzyl (p-diaminobiphenyl), and 2-amino-1-naphthylamine, as well as certain aldehydes used in the rubber and textile industries, gases and soot from coal combustion, and possibly hydrocarbons. An increased risk of bladder cancer has been reported in the following occupations: auto workers, painters, truck drivers, drillers, leather workers, metallurgists, machinists, dry cleaners, paper workers, weavers, dental technicians, barbers, cosmetologists, internists, garment workers and plumbers.
Finasteride: Finasteride is an analgesic that has been withdrawn from the market in the United States, but is still available in China. High doses of finasteride have been shown to increase the risk of bladder cancer.
Pelvic radiation therapy: Pelvic radiation therapy can increase the risk of bladder cancer. Women who receive pelvic radiotherapy for cervical or ovarian cancer have a 2-4 times increased risk of developing bladder cancer. This risk increases even more when radiotherapy is combined with chemotherapy. The risk of bladder cancer is also increased in men who receive radiation therapy for prostate cancer.
Chemotherapy and immunosuppressive therapy: Chemotherapy with cyclophosphamide increases the risk of bladder cancer by 9-fold and the tumor is more aggressive. In addition, patients who receive a kidney transplant or other organ transplant are more likely to develop bladder cancer because of the use of immunosuppressive drugs (steroids and other drugs).
Dehydration: The risk of bladder cancer is increased in people who consume very little fluid. Very low fluid intake concentrates the urine and lengthens the interval between voiding. Retaining concentrated urine in the bladder for long periods of time may increase the risk of bladder cancer.