Bladder cancer refers to any of several types of malignant growths of the urinary bladder. It is a disease in which abnormal cells multiply without control in the bladder. The bladder is a hollow, muscular organ that stores urine; it is located in the pelvis. The most common type of bladder cancer begins in cells lining the inside of the bladder and is called urothelial cell or transitional cell carcinoma (UCC or TCC).

Signs and symptoms

Bladder cancer characteristically causes blood in the urine; this may be visible to the naked eye (frank haematuria) or detectable only by microscope (microscopic hematuria). Other possible symptoms include pain during urination, frequent urination (Pollakiuria) or feeling the need to urinate without results. These signs and symptoms are not specific to bladder cancer, and are also caused by non-cancerous conditions, including prostate infections and cystitis.

Risk factors

Exposure to environmental carcinogens of various types is responsible for the development of most bladder cancers. In a 10-year study involving almost 48,000 men, researchers found that men who drank 1.5L of water a day had a significantly reduced incidence of bladder cancer when compared with men who drank less than 240mL (around 1 cup) per day. The authors proposed that bladder cancer might partly be caused by the bladder directly contacting carcinogens that are excreted in urine. Drinking high quantitites of water dilutes the urine and will reduce contact time that the carcinogens spend in our bladder, potentially reducing our chance of disease. Tobacco use (specifically cigarette smoking) is thought to cause 50% of bladder cancers discovered in male patients and 30% of those found in female patients.Fact: date=August 2007 Thirty percent of bladder tumors probably result from occupational exposure in the workplace to carcinogens such as benzidine. Occupations at risk are metal industry workers, rubber industry workers, workers in the textile industry and people who work in printing. Some studies also suggest that auto mechanics have an elevated risk of bladder cancer due to their frequent exposure to hydrocarbons and petroleum-based chemicals. Hairdressers are thought to be at risk as well because of their frequent exposure to permanent hair dyes. It has been proposed that hair dyes are a risk factor, and some have shown an odds ratio of 2.1 to 3.3 for risk of developing bladder cancer among women who use permanent hair dyes, while others have shown no correlation between the use of hair dyes and bladder cancer. Certain drugs such as cyclophosphamide and phenacetin are known to predispose to bladder TCC. Chronic bladder irritation (infection, bladder stones, catheters, bilharzia) predisposes to squamous cell carcinoma of the bladder. Approximately 20% of bladder cancers occur in patients without predisposing risk factors.

Genetics

Like virtually all cancers, bladder cancer development involves the acquisition of mutations in various oncogenes and tumor supressor genes. Genes which may be altered in bladder cancer include H19, FGFR3, HRAS, RB1 and TP53. Several genes have been identified which play a role in regulating the cycle of cell division, preventing cells from dividing too rapidly or in an uncontrolled way. Alterations in these genes may help explain why some bladder cancers grow and spread more rapidly than others.Fact: date=April 2008