The United States and Europe have the highest incidence of bladder cancer.
Cigarette smokers develop bladder cancers almost three times as often as nonsmokers. Smoking may be responsible for 50 percent of bladder cancers in men and 40 percent in women. This relationship may be due to a substance called 4-ABP, a carcinogen found in tobacco smoke and the blood of smokers and which is known to induce bladder cancer. This substance disappears from blood within 90 to 120 days after a person stops smoking.
The relationship of tumors to the use of artificial sweeteners such as cyclamates and to coffee drinking is questionable. Recent studies have completely failed to find any risk above that of the general population.
Because chemical carcinogens and their breakdown products pass through the kidney down the urinary tract, the whole urothelial tract is exposed to these irritants and is at risk for forming new tumors. This is why people cured of one urothelial tract tumor have to be followed closely throughout their lifetime.
Those with a renal pelvis cancer, for example, are 21 times more at risk to develop another urinary tract tumor compared with the general population. Ten to 20 percent of those with a bladder cancer have been found to develop a superficial urethral tumor.
A good deal of work is now being done to evaluate agents that can prevent the development of such tumors. Much has been written about the testing of certain vitamin A derivatives for preventing tumors and for making early tumors revert back to normal cells . But high doses of the derivatives now marketed (vitamin A itself or beta-carotene) should be avoided, since the doses needed to prevent new tumors produce severe liver toxicity.
