Urinary tract infection and risk of bladder cancer.

In an epidemiologic study of 2982 bladder carcinoma patients and 5782 population controls from 10 geographic areas of the United States, the role of urinary tract infection and inflammation in the etiology of this neoplasm was evaluated. A history of urinary tract infection significantly elevated the risk of bladder cancer, particularly in individuals who reported three or more infections (relative risk (RR) = 2.0). Significantly increased bladder cancer risk was also found for bladder stones (RR = 1.8), while kidney stones showed no relation. A history of three or more urinary tract infections was strongly related to squamous cell carcinoma in particular (RR = 4.8).