Benign tumours of the bladder, including inverted papilloma and nephrogenic adenoma, are uncommon. The vast majority of primary bladder cancers are malignant and epithelial in origin.
- >90% are transitional cell carcinoma (TCC)
- 1-7% are squamous cell carcinoma (SCC)
- 75% are SCC in areas where schistosomiasis is endemic
- 2% are adenocarcinoma
- Rarities include phaeochromocytoma, melanoma, lymphoma, and sarcoma arising within the bladder muscle
- Secondary bladder cancers are mostly metastatic adenocarcinoma from gut, prostate, kidney or ovary
Men are 2.5 times more likely to develop the disease than women, the reasons for which are unclear but may be associated with greater urine residuals in the bladder.
Age increases your risk, most commonly diagnosed in the 8th decade and rare in those under 50 years old.
Smoking is the major cause of bladder in the developed world. Cigarette smoke contains the carcinogens 4-aminobiphenyl (4-ABP) and 2-naphthylamine. Slow hepatic acetylation (detoxification) of 4-ABP by N-acetyltransferase and glutathione S-transferase M1 (GST M1), or induction of cytochrome p-450 1A2 demethylating enzyme, appear to increase urinary carcinogenic exposure of urothelium.
Smokers have a 2-5 fold risk compared to non-smokers, with respect to development of bladder cancer and subsequent recurrences. Estimates suggest that 30-50% of bladder cancer is caused by smoking.
Exposure to carcinogens, in particular aromatic hydrocarbons like aniline, is a recognized cause of bladder cancer.
Some examples of high risk occupations: Hairdressers, Plumbers, Painters, Drivers exposed to diesel exhaust and Chemical manufacturing.