Mortality reduction of breast cancer in Canada: Beneficial impact of cancer care infrastructure

Abstract

649 Background: Survival after breast cancer has been improving in the last two decades. This study examines breast cancer population mortality in Canada over the last 25 years, with two main objectives: 1) To determine the impact of evolving therapy and diagnostic interventions between 1979–2003; and 2) To identify differences between the provinces of Canada, and if these could be accounted for by different cancer care infrastructures (provincial guidelines and community outreach programs, funding, etc.) Methods: Annual age-standardized mortality rates per 100,000 for breast cancer in different provinces of Canada were evaluated, using Statistics Canada Data for the years 1979–2003. Relative changes in mortality between the baseline period (average values, years 1979–83), and subsequent 5 year periods were computed for all Canada and for regions with differing organizational structure of cancer care, and expressed both as Relative % change from baseline (Mortality % Change) and as an Absolute age-standardized mortality (deaths per 100,000 population), both averaged for each of the sequential 5-year periods. Results: Conclusions: These data provide evidence for a substantial population mortality reduction in Canada, seen also in other parts of the western world. These trends probably reflect the interaction of all interventions including adjuvant systemic therapy, screening mammography, education, etc. Furthermore, in BC, the first Canadian province with implementation of provincial guidelines and well-funded community outreach since mid-1970s, the mortality reductions were observed earlier, and to a larger degree, than in other Canadian provinces. Thus, these data would suggest an association between mortality reduction and organization of cancer care, such as implementation of cancer guidelines, community work, and associated funding. No significant financial relationships to disclose.