Description

• Primary malignant neoplasms arising in the urinary bladder
• There are three types that begin in cells in the lining of the bladder: transitional cell carcinoma, squamous cell carcinoma, and adenocarcinoma.
• Most common type is transitional cell carcinoma (90%) (1).
• The spectrum of bladder cancer includes nonmuscle invasive, muscle invasive, and metastatic disease.
• Rhabdomyosarcoma of the bladder may occur in children.

Epidemiology

Incidence

• Increases with age (median age at diagnosis is 73 years) (2)
• More common in Caucasians than in Asians or African Americans
• Male > female (4:1); but in smokers, risk is 1:1.
• 34.2/100,000 men per year (2)
• 8.5/100,000 women per year
• 19.7/100,000 men and women per year (2)

Prevalence
In 2018, 723,745 cases in the United States (2)

Etiology and Pathophysiology

Unknown, other than related to risk factors:

• 75% is nonmuscle invasive (in lamina propria or mucosa) (3):
  • Usually highly differentiated with long survival
  • Initial event seems to be the activation of an oncogene on chromosome 9 in superficial cancers (1).
• 25% of tumors are muscle invasive (deeper than lamina propria) at presentation (3):
  • Tend to be high grade with worse prognosis
  • Associated with other chromosome deletions

Genetics
Genetic effects may play a direct role in the initiation and progression of bladder cancer. Most studies showed a small increase in risk in relatives of those with bladder cancer. Patients with Lynch syndrome has up to 20% lifetime risk of developing bladder cancer.

Risk Factors

• Smoking is the single greatest risk factor (increases risk 4-fold) and increases risk equally for men and women (4).
• There is a slight but significant increased risk with the use of pioglitazone, possibly in a dose- and time-dependent manner; may also be present with other thiazolidinediones (5)
• Other risk factors (4):
  • Positive family history, especially in relatives diagnosed before age 60 years
  • Occupational carcinogens in dye, rubber, paint, plastics, metal, carbon black dust, petroleum, and automotive exhaust
  • Schistosomiasis in Mediterranean (squamous cell) cancer
  • Arsenic in well water
  • History of bladder radiation, pelvic irradiation, or certain anticancer drugs like cyclophosphamide or ifosfamide
  • Chronic lower UTI
  • Chronic indwelling urinary catheter
  • Cyclophosphamide exposure

General Prevention

• Avoid smoking and other risk factors.
• Counseling of individuals with occupational exposure
• The U.S. Preventive Services Task Force has concluded that there is insufficient evidence to determine the balance between risk and harm of screening for bladder cancer.

Commonly Associated Conditions

Smoking