Bladder Cancer

Bladder cancer is a malignant neoplasm originating from the epithelial lining (urothelium) of the urinary bladder. It most commonly presents as transitional cell carcinoma (urothelial carcinoma) and can range from superficial, non-invasive tumors to invasive muscle-invasive disease.

Definition

Epidemiology

Accounts for ~3% of all cancers worldwide
More common in men than women (3:1 ratio)
Peak incidence in individuals aged 60–80 years
Major risk factors include tobacco smoking, occupational exposure to aromatic amines, and chronic bladder irritation
Recurrence rates are high even after treatment, particularly for non-muscle invasive tumors

Etiology

Urothelial carcinoma (transitional cell carcinoma) is most common (~90%)
Other histologic types: squamous cell carcinoma, adenocarcinoma, small cell carcinoma
Risk factors: smoking, occupational exposure to chemicals (dyes, rubber, leather), chronic urinary tract infections, schistosomiasis, long-term indwelling catheters
Genetic mutations: TP53, FGFR3, RB1, and others involved in tumorigenesis
Carcinogenic exposure leads to DNA damage and urothelial cell transformation

Pathophysiology

Normal urothelial cells accumulate genetic mutations leading to uncontrolled proliferation
Non-muscle invasive tumors remain confined to the mucosa/submucosa; muscle-invasive tumors invade detrusor muscle and potentially metastasize
Angiogenesis and local immune evasion facilitate tumor growth and recurrence
Advanced disease can invade surrounding tissues, lymph nodes, and distant organs
Field cancerization effect: multiple tumors may develop in different areas of the urothelium