Emerging clinical uses for GM-CSF

Abstract

variety early in life. Quitting smoking is associated with a dramatic drop in the risks of bladder cancer [7], irrespective of the type of tobacco. In the two studies which considered the effect of quitting separately by type, the relative risk remained well above the level of non-smokers only for smokers of black tobacco. The study of time-related variables is complex, since they are strictly correlated. Only if a large proportion of the subjects stopped smoking and then started again several times, a distinction between duration, age started and time since quitting can be made on statistical grounds; usually, however, such a distinction cannot be made [9]. The overall picture concerning the type of tobacco and bladder cancer, as far as time-related variables are concerned, seems to be the following: in general, tobacco smoking mainly exerts a “late stage” action, as is clearly indicated by the rapid drop in risks after discontinuation. Black tobacco, however, seems to have also an “early stage” action, as suggested by the stronger association with age at start, the fact that the relative risks remain high after 10 or 15 years since quitting and the fact that switching to blond tobacco does not seem to be different from continuing to smoke black tobacco.