Associations between bladder cancer risk factors and tumor stage and grade at diagnosis

Using data on 1,860 bladder cancer cases and 3,934 population-based controls from the National Bladder Cancer Study, we examined associations between suspected bladder cancer risk factors and tumor stage and grade. Employment in a high-risk occupation was associated with the entire clinical spectrum of bladder cancer rather than a particular tumor stage or grade. For example, relative risks (RR) were similar for noninvasive and invasive disease (1.5 and 1.6, respectively). Cigarette smoking also increased risk of the entire clinical spectrum of bladder cancer, but the more advanced the stage, the stronger the effect. For example, relative risks of noninvasive and invasive bladder cancer for current heavy smokers were 3.0 and 5.2, respectively. Cigarette smoking was associated with higher risk of low-grade than high-grade tumors, once stage of disease was taken into account. Compared with whites, nonwhites were at a lower risk of noninvasive bladder cancer (RR = 0.4) but at similar risk of invasive bladder cancer (RR = 1.1), a pattern indicating racial differences in health practices related to bladder cancer detection. History of urinary tract infections and bladder stones was associated with increasing relative risks for advanced tumor stage. Heavy artificial sweetener use was associated with higher-grade, poorly differentiated tumors. Coffee consumption and family history of bladder cancer were not consistently associated with tumor stage or grade. Overall, different clinical presentations of bladder cancer share most suspected bladder cancer risk factors, including employment in a high-risk occupation and cigarette smoking.