Breast cancer mortality significantly dropped at 10 years of follow-up, attenuated after 10 years
MONDAY, Aug. 17, 2020 (HealthDay News) — Annual mammography from age 40 years is associated with a relative reduction in breast cancer mortality for 10 years, according to a study published online Aug. 12 in The Lancet Oncology.
Stephen W. Duffy, from Queen Mary University of London, and colleagues conducted a randomized trial involving 23 breast screening units across Great Britain. Women aged 39 to 41 years were randomly assigned to either yearly mammographic screening from the year of inclusion in the trial until age 48 years (intervention group) or to standard care of no screening until invitation to a screening program at about age 50 years (control group) in a 1:2 ratio (53,883 and 106,953 women, respectively).
Women were followed for a median of 22.8 years. The researchers identified a significant reduction in breast cancer mortality at 10 years of follow-up, with 83 and 219 breast cancer deaths in the intervention and control groups, respectively (relative rate, 0.75; 95 percent confidence interval, 0.58 to 0.97; P = 0.029). Thereafter, there was no significant reduction, with 126 and 255 deaths occurring after more than 10 years of follow-up (relative rate, 0.98; 95 percent confidence interval, 0.79 to 1.22; P = 0.86).
“This is a very long-term follow-up of a study which confirms that screening in women under 50 can save lives,” Duffy said in a statement. “The benefit is seen mostly in the first 10 years.”
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