Bladder Cancer (Squamous Cell Carcinoma of the Bladder)

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What is Bladder Cancer?

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Squamous Cell Carcinoma of the Bladder is a rarer type of bladder cancer. The majority of bladder cancers are transitional cell carcinomas that arise in the urinary tract epithelium and can also occur in parts of the kidney, ureter and urethra (tubes carrying urine from the kidney and urinary bladder respectively). The bladder functions as a waste storage system for urine. Urine is produced by the kidneys as they filter the blood. The urine then travels down the ureters into the bladder. The bladder expands and once it reaches a certain maximum volume, the urge to pass urine increases until urine is passed. The bladder is made up of an elastic type tissue which contains a layer of muscle. The bladder is lined with epithelium called transitional cells which are tall, thin cells that protect the underlying bladder from the urine contained therein. Because the bladder is lined with transitional epithelium, the usual type of cancer affecting the bladder is transitional cell carcinoma. However, in response to chronic irritation the epithelial lining of the bladder can gradually change to squamous (similar to the skin). With further exposure to irritative or carcinogenic agents - bladder cancer can develop.

Who gets Bladder Cancer?

Bladder cancer on the whole is the most common malignancy affecting the urinary system. The majority of cases are transitional cell carcinomas affecting the tall epithelial cells lining the bladder. Squamous cell carcinoma accounts for only 3 to 7% of bladder cancers in Western countries, but in certain countries where parasites are very common (especially schistosomiasis) it is found much more frequently. The parasites cause chronic irritation of the bladder causing the cells to change their shape to try to protect the bladder. Over time the cells can change to become neoplastic or cancerous. In these countries up to 70% of bladder cancers are the squamous type. The incidence of bladder cancer increases with age and 80% of patients are found to be between 50 and 80 years. Men: bladder cancer is much more common in men and is the fourth most common cancer. In Australia approximately 554 men die from bladder cancer each year. However, squamous cell carcinoma accounts for only a small percentage. Women: Bladder cancer is the tenth most common cancer in women. Approximately 250 Australian women die from bladder cancer each year. However, squamous cell carcinoma accounts for only a small percentage.

Predisposing Factors

bladder cancer is almost exclusively found in bladders exposed to chronic irritation and infection. It is primarily a bladder disease of developing countries and is twice as common in white people compared to blacks. In African countries, Schistosoma haematobium is a parasitic infection of the bladder transmitted by freshwater snails and is acquired when people bathe in slow-moving freshwater rivers and lakes. The eggs of the parasite cause chronic inflammation of the bladder and ureters - and more frequently leads to obstructive kidney disease, but can also cause bladder cancer. In the United States chronic inflammation of the bladder is more often due to long-term indwelling urinary catheters or other instrumentation, and bladder stones.

Progression

Bladder cancer initially spreads to involve larger areas of the mucosa of the bladder, with deeper invasion later. Finally metastatic spread to other organs via the blood stream and lymphatics can occur. At the time of discovery most bladder tumours are deeply invasive.

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