Bladder cancer

Bladder cancer

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 transitional cell carcinoma (sometimes urothelial cell carcinoma).

Signs and symptoms

Bladder cancer characteristically causes blood in the urine; this may be visible to the naked eye (frank hematuria) or detectable only by microscope (microscopic hematuria). Other possible symptoms include pain during urination, frequent urination (Polyuria) 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. Kidney cancer also can cause hematuria.

Causes

Tobacco smoking is the main known cause of urinary bladder cancer: in most populations, smoking causes over half of bladder cancer cases in men and a sizeable proportion in women. There is a linear relationship between smoking and risk, and quitting smoking reduces the risk.^[2] 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. It is postulated, therefore, that by drinking higher quantities of water, urine is more dilute, thereby reducing the chance of disease.^{[citation needed]} Thirty percent of bladder tumors probably result from occupational exposure in the workplace to carcinogens such as benzidine. 2-Naphthylamine, which is found in cigarette smoke, has also been shown to increase bladder cancer risk. 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.^[3] 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.^{[citation needed]} Certain drugs such as cyclophosphamide and phenacetin are known to predispose to bladder TCC.^{[citation needed]} Chronic bladder irritation (infection, bladder stones, catheters, bilharzia) predisposes to squamous cell carcinoma of the bladder.^{[citation needed]} Approximately 20% of bladder cancers occur in patients without predisposing risk factors.^{[citation needed]}

Diagnosis

The gold standard for diagnosing bladder cancer is biopsy obtained during cystoscopy. Sometimes it is an incidental finding during cystoscopy.^[4] Urine cytology can be obtained in voided urine or at the time of the cystoscopy ("bladder washing"). Cytology is very specific (a positive result is highly indicative of bladder cancer) but suffers from low sensitivity (a negative result does not exclude the diagnosis of cancer). There are newer urine bound markers for the diagnosis of bladder cancer. These markers are more sensitive but not as specific as urine cytology. They are much more expensive as well. Many patients with a history, signs, and symptoms suspicious for bladder cancer are referred to a urologist or other physician trained in cystoscopy, a procedure in which a flexible tube bearing a camera and various instruments is introduced into the bladder through the urethra. Suspicious lesions may be biopsied and sent for pathologic analysis