CIGARETTE-SMOKING AND RISK OF PROSTATE-CANCER - A POPULATION-BASED CASE-CONTROL STUDY IN ONTARIO AND BRITISH-COLUMBIA, CANADA

The relationship between cigarette smoking and risk of prostate cancer was examined in a case-control study conducted in Ontario and British Columbia, Canada, In each centre, cases were men with a histologicall y confirmed diagnosis of adenocarcinoma of the prostate notified to th e provincial cancer registry, In Ontario, controls were selected rando mly from assessment lists maintained by the Ontario Ministry of Revenu e and were frequency matched to the cases on age, In British Columbia, controls were also frequency matched to the cases on age and were sel ected randomly from a roster maintained by the Medical Services Plan o f British Columbia, The study in Ontario was conducted between April 1 990 and April 1992, and that in British Columbia was conducted between January 1989 and December 1991, In all, the study included 408 cases (207 in Ontario and 201 in British Columbia) and 407 controls (207 in Toronto and 200 in British Columbia (one case was unmatched)), Overall , there was little variation in risk of prostate cancer with pack-year s of cigarette consumption (filter and non-filter cigarettes combined) , and there was no evidence for an effect confined to filter or non-fi lter cigarettes, There was some evidence for a positive association wi th non-filter cigarettes in British Columbia, but on formal testing fo r heterogeneity, this finding was not inconsistent with the absence of an association in Ontario, There was also little variation in risk by years since first smoked or (for ex-smokers) by years since quitting, These data provide little support for an association between cigarett e smoking and prostate cancer risk.