Significant reduction in advanced breast cancer. Results of the first seven years of mammography screening in Kopparberg, Sweden

Abstract

A population-based, randomized, controlled breast cancer screening trial with single-view mammography as the only means of primary detection has been under way in Kopparberg county, Sweden, since October 1977. The 7-year results of the study show (1) a significant change in the stage distribution of breast cancers in the cohort invited to undergo screening (ASP) as compared to the control group. (2) This change is seen as an initial decrease in the proportion of advanced (stage II and more advanced) cancers in the ASP as compared to the control population, followed in the second and third round of screening by a significant decrease in the absolute number of these advanced cancers in the ASP relative to the control group. (3) A thorough follow-up of both populations will answer whether these preliminary findings will result in decreased breast cancer mortality in the population invited to screening.