What Is the Main Cause of Bladder Cancer?

The cause of most bladder cancers is unknown but genetic changes may play a role. 

Risk factors for developing bladder cancer include:

• Smoking is the main risk factor for bladder cancer and is responsible for about half of all bladder cancers in both men and women
• Workplace exposures to certain chemicals
  • Aromatic amines, such as benzidine and beta-naphthylamine, sometimes used in the dye industry
  • Makers of rubber, leather, textiles, paint products, and printing companies
  • Painters, machinists, printers, hairdressers (exposure to hair dyes), and truck drivers (exposure to diesel fumes)
• Certain medicines or herbal supplements
  • Pioglitazone (Actos), used to treat diabetes
  • Dietary supplements containing aristolochic acid (mainly in herbs from the Aristolochia family) 
• Arsenic in drinking water
  • Not a major problem in the U.S. but may be in other parts of the world
• Not drinking enough fluids
• Race and ethnicity
  • People of European descent are two times more likely to develop bladder cancer than African Americans and Hispanics
  • Asian Americans and native American Indians have slightly lower rates 
• Age
  • About 90% of people who develop bladder cancer are over 55 years
• Gender
  • More common in men than in women
• Chronic bladder irritation and infections
  • Urinary infections (UTIs), kidney and bladder stones, bladder catheters left in place for a long time, and other causes of chronic bladder irritation 
  • Schistosomiasis (bilharziasis), is a parasitic worm infection that can get into the bladder
    • More common in Africa and the Middle East; rare in the U.S.
• Personal history of bladder or other urothelial cancer
• Bladder birth defects
• Genetics and family history
• Chemotherapy or radiation therapy
  • Chemotherapy drug cyclophosphamide (Cytoxan)
  • Radiation to the pelvis 

Causes of bladder cancer are often genetic, and risk factors include smoking, chemical exposure, race, age and other variables.

Bladder cancer is a type of cancer that occurs when cells in the bladder become abnormal and grow out of control. 

Types of bladder cancers include: 

• Urothelial carcinoma, also known as transitional cell carcinoma (TCC): the most common type of bladder cancer 
• Squamous cell carcinoma: only about 1% to 2% of bladder cancers are squamous cell carcinomas
• Adenocarcinoma: only about 1% of bladder cancers are adenocarcinomas
• Small cell carcinoma: less than 1% of bladder cancers 
• Sarcoma: very rare

Bladder cancer is often discovered early because it causes blood in the urine or other urinary symptoms that cause a person to see a doctor. Many of the symptoms are more likely to be caused by something other than bladder cancer, but it’s important to have them checked.

Symptoms of bladder cancer include: 

• Blood in the urine (hematuria)
• Usually the first sign of bladder cancer
• Urine may appear orange, pink, or, less often, dark red
• Changes in bladder habits 
  • Bladder irritation
  • Urinary frequency
  • Pain or burning during urination
  • Feeling as if you need to go right away, even when the bladder isn't full
  • Difficulty urinating or having a weak urine stream
  • Urinating multiple times during the night (nocturia)

Symptoms of advanced bladder cancers that have grown large or have spread to other parts of the body may include:

• Inability to urinate
• Lower back pain on one side
• Loss of appetite
• Weight loss
• Feeling tired or weak
• Swelling in the feet
• Bone pain

Bladder cancer is diagnosed with a physical exam which may involve a digital rectal exam (DRE) and in women, a pelvic exam. 

Tests used to diagnose bladder cancer include: 

• Urine tests
  • Urinalysis
  • Urine cytology
  • Urine culture
  • Urine tumor marker tests
• Cystoscopy
• Biopsy using transurethral resection of bladder tumor (TURBT)
• Imaging tests
• Intravenous pyelogram (IVP)
• Retrograde pyelogram
• Computed tomography (CT) scans 
  • CT urogram
  • CT-guided needle biopsy
• Magnetic resonance imaging (MRI) scans
  • MRI urogram
• Ultrasound
  • Ultrasound-guided needle biopsy
• Chest X-ray
• Bone scan

Treatment for bladder cancer may involve one or more of the following:

• Bladder cancer surgery
  • Transurethral resection of bladder tumor (TURBT) or a transurethral resection (TUR): most common treatment for early-stage or superficial (non-muscle invasive) bladder cancers
  • Surgical removal of all or part of the bladder (radical or partial cystectomy): for invasive bladder cancer
  • Reconstructive surgery after radical cystectomy: if the entire bladder is removed, patients need another way to store urine and pass it out of the body
• Intravesical therapy: liquid drug administered into the bladder 
• Chemotherapy 
• Radiation therapy 
• Immunotherapy 
  • Immune checkpoint inhibitors: atezolizumab (Tecentriq), durvalumab (Imfinzi), avelumab (Bavencio), nivolumab (Opdivo), and pembrolizumab (Keytruda) 
• Monoclonal antibodies
  • Enfortumab vedotin (Padcev) 
• Targeted therapy drugs 
  • Erdafitinib (Balversa)

Life expectancy for bladder cancer is often expressed in 5-year survival rates, that is, how many people will be alive 5 years after diagnosis. 

Bladder cancer 5-year survival rates by stages are:

• In situ (cancer is still confined to the cells in which it initially started and has not spread into any nearby tissue): 96%
• Localized (no sign cancer has spread outside the bladder): 70%
• Regional (cancer has spread outside the bladder to nearby structures or lymph nodes): 36%
• Distant (cancer has spread to distant parts of the body, such as the lung, liver, or distant lymph nodes): 5%

There is no definite way to prevent bladder cancer but some factors can be controlled to lower the risk of developing it, such as:

• Don’t smoke
  • Smoking is believed to cause about half of all bladder cancers
• Limit exposure to certain chemicals in the workplace
  • Follow proper work safety practices in workplaces with chemical exposure risks
• Drink adequate amounts of liquids
• Eat plenty of fruits and vegetables