Downward trend in prostate cancer mortality in Quebec and Canada

Purpose: if new treatment strategies and screening for prostate cancer are effective they should reduce prostate cancer mortality. In this review we monitored prostate cancer mortality rates in Quebec and in Canada. Materials and Methods: We obtained data on all deaths from prostate cancer between 1976 and 1997 in Quebec, and 1976 and 1996 in Canada. We calculated age standardized mortality rates and assessed changes with time. Results: Prostate cancer mortality rates increased regularly until 1991 in Quebec and Canada. After 1991 the rates decreased moderately until 1995 and then more markedly in 1996. There was a further decline in 1997 in Quebec. Overall, age standardized prostate cancer mortality rates declined by 23% in Quebec between 1991 and 1997, and by 9.6% in Canada between 1991 and 1996. The mortality decline was observed for all age groups but was more pronounced among men younger than 75 years. Conclusions: Until 1995 the trends in prostate cancer mortality in Quebec and Canada were similar to those observed in the United States. Our data suggest that a sharper decline has occurred since 1995. It is of primary importance to identify the causes of the mortality decline. As prostate cancer mortality rates declined relatively early after the initiation of widespread screening with prostate specific antigen, it is unlikely that screening has as yet contributed in a major way to the decline. It is more likely that the mortality reduction is a consequence of better prostate cancer management or improved treatment modalities.