Smoking and Cancer of the Lower Urinary Tract

Interviews were conducted with 470 patients with transitional or squamous-cell carcinoma of the lower urinary tract, more than 90 per cent of whom had a bladder tumor. An age-stratified and sex-stratified but otherwise random sample of 500 persons drawn from the population of the entire study area was also interviewed as a control. Among men, cigarette smokers have a relative risk of bladder cancer of 1.89 as compared with nonsmokers, and about 39 per cent of the cases are related to smoking. This amounts to 16.4 cases per year per 100,000 men 20 years of age and over. Among women 20 years of age and over, the comparable figures are 2.00, 29 per cent and 3.9 cases per year per 100,000. For both sexes risk is increased among those who smoked heavily and those who inhaled. None of the excess risk of bladder cancer associated with cigarette smoking is explained by any indirect association with occupational experience. No significant risk is associated with pipe or cigar smoking. The data also suggest that incidence rates will increase during the next decade or so, especially among women.