Buckle Up for Breast Cancer—Deaths from Breast Cancer Can Be Analyzed in the Same Way as Deaths in Automobile Accidents

Abstract

Background:Randomized population mammographic screening trials demonstrated a statistically significant mortality reduction in screened women. Studies in Sweden and The Netherlands show that screening is the main reason that the death rate has decreased in the general population, but ony limited data are available to assess this in the US. In a previous report, 75% of breast cancer deaths occurred in the small proportion of unscreened women. This conclusion needs confirmation.Methods:In a large hospital consortium, 6,997 invasive breast cancer diagnoses occurred between 1990 and 1999. Among all subsequent deaths through 2007, breast cancer deaths in Massachusetts women were documented by review of hospital and outpatient records. Regular screening was defined as two or more screening mammograms at intervals of two years or less in asymptomatic women.Results:After 12.5 (range: eight to 17) years of median follow-up, 461 deaths from breast cancer were confirmed. Seventy-two deaths (15.6%) resulted from non-palpable screen-detected cancers, 44 deaths (9.6%) resulted from palpable interval cancers, and a total of 116 deaths (25.2%) occurred in regularly screened women. Three hundred and twenty-two deaths (69.9%) occurred in women who had never had screening mammography, and 23 deaths (5%) occurred after one or more previous mammograms, none within two years of diagnosis. Thus, 345 breast cancer deaths (74.8%) occurred in women who were not regularly screened.Conclusion:The most effective method of avoiding death from breast cancer is for women to participate in regular screening mammography.