Reduction in Mortality Observed with Invitation to Mammography Screening
Effect of Screening Program on Breast Cancer Mortality Analyzed
Invitation to screening with modern mammography is associated with a 28% reduction in deaths from breast cancer, according to research published June 17 in BMJ.
Harald Weedon-Fekjaer, of the Norwegian University of Science and Technology in Trondheim, and colleagues conducted a prospective cohort study of Norwegian women, aged 50 to 79, who were followed between 1986 and 2009. The researchers examined the effectiveness of a national mammography screening program involving biennial invitations, sent to women aged 50 to 69 years, from 1995 to 2005.
The researchers found, following adjustment for multiple variables, including age, birth cohort, and national trends in deaths from breast cancer, that the mortality rate ratio associated with invitation to mammography screening was 0.72 (95 percent confidence interval [CI], 0.64 to 0.79). To prevent one death from breast cancer, the number of women who would need to be invited to mammography screening was 368 (95 percent CI, 266 to 508).
"The Norwegian study largely confirms what is already known: The benefits of screening mammography are modest at best," the authors of an accompanying editorial write. "While the benefits are small, the harms of screening are real and include overdiagnosis, psychological stress, and exorbitant health care costs."