Objective: To quantify the risks of urothelial cancer associated with smoking cigarettes.
Subjects and methods: Histories were taken from 989 patients diagnosed with urothelial cancer, 2059 electoral register controls and 1599 General Practitioner controls. Histories of patients and controls were compared by means of logistic regression.
Results: Statistically significant trends were observed for the risk of urothelial cancer to increase with estimated lifetime consumption of cigarettes. Among ex-smokers, risks reduced with time since quitting, and ex-smokers who quit 20 or more years ago experienced risks similar to lifelong non-smokers. Type of cigarette was not an important predictor of risk. The two control series provided estimates of 45% and 33% respectively for the percentage of cancers in the series attributable to cigarette smoking.
Conclusion: Cigarette smoking is the single most important cause of urothelial cancer, but stopping smoking leads quickly to reductions in risk.