Bladder Cancer Facts

November 25, 2024

This page was reviewed under our medical and editorial policy by Kevin G. Chan, M.D., clinical professor, division of urology and urologic oncology, Department of Surgery, City of Hope^® Cancer Center Duarte

In the United States, approximately 84,870 new cases of bladder cancer are diagnosed each year. Men are more prone to the disease. About 1 in 28 men and 1 in 89 women will develop bladder cancer during their lifetimes. 

This guide to bladder cancer causes and risk factors aims to help patients and their families find out more about this disease.

What Is Bladder Cancer?

The bladder is a hollow, sac-like organ positioned in the pelvis between the hip bones that stores urine. Urine is produced after blood has been filtered by the kidneys to remove excess fluid and toxins. The movement of urine from the kidneys is propelled by two ureters, the tubes that connect the kidneys to the bladder. The bladder expands and contracts as it fills with urine and as urine is emptied from the body. The urine exits through a tube called the urethra.

The bladder is a complex organ, comprised of several layers of tissue. Bladder cancer begins when abnormal cells develop in one or more of these layers, forming a tumor. Usually, it begins in tissue that makes up the bladder’s inner lining, which is comprised of urothelial cells. Urothelial carcinoma, also known as transitional cell carcinoma, is the most common type of bladder cancer.

However, over time, bladder cancer may spread into the bladder wall or the lymph nodes or other organs.

What Causes Bladder Cancer?

The exact cause of bladder cancer is not known, but researchers have identified some factors that may increase a person’s lifetime risk for developing this cancer.

These risk factors may be linked to DNA changes in the body, causing mutations in the parts of cells that control growth. These mutations change how bladder cells behave, allowing them to grow abnormally, which may cause cancer cells to form.

Gene changes that occur during a person’s life sometimes happen randomly, without a known cause. Other times, exposure to chemicals that cause cancer, such as tobacco smoke, may be what prompts cells in the bladder to mutate. About 50% of people diagnosed with bladder cancer have a history of smoking.

What Increases the Risk of Bladder Cancer?

These risk factors have been linked to the disease, but having a risk factor does not mean each person will receive a bladder cancer diagnosis.

Smoking: Smoking causes approximately half of all bladder cancer cases and smokers are three times more likely to get bladder cancer compared to nonsmokers.

Age: Approximately 90% of cases are diagnosed in people older than 55.

Gender: Bladder cancer is more common in men.

Chronic bladder infections or irritations: Repeated infections and prolonged use of urinary catheters have been linked to the disease.

Workplace chemical exposures: Chemicals called aromatic amines, used in the dye industry, may cause bladder cancer. People who work in printing, painting, textiles and hairdressing industries may have a higher bladder cancer risk.

Prior treatment with radiation therapy: People who have undergone radiation therapy in the pelvic area or with chemotherapy are at increased risk.

Genetic mutations: Having certain changes in the genes that are linked to bladder cancer, such as Lynch syndrome or Cowden disease, have been linked to the disease.

Fluid intake: People who don’t consume an adequate volume of fluids each day (such as water) may have a higher risk of developing bladder cancer.

Is Bladder Cancer Hereditary?

Except in rare cases, most bladder cancer is not hereditary, meaning it is not typically passed down directly in families. More often, it is linked to genetic mutations that occur over the course of a person’s life as a result of factors that cannot be controlled (e.g., age, gender), as well as the lifestyle and chemical exposures outlined above, rather than from genes present at birth.