Expanding the national breast screening to women aged 40-49 years could save more than 620 lives, with minimal increased overdiagnosis, according to a study led by Queen Mary University of London that looked at data from 160,000 women.
The new article, published in the Lancet Oncology, presents 23-year follow-up results from the UK Breast Screening Age Trial.
A total of 160,921 women were recruited between 14 October 1990 and 24 September 1997. Of these, 53,883 (33.5%) were assigned to the intervention group and 106,953 (66.5%) to the control group. Women were followed up for a median of 22.8 years.
The study revealed a significant reduction in breast cancer mortality at 10 years of follow-up, with 83 breast cancer deaths in the intervention group versus 219 in the control group (relative rate [RR], 0.75; 95% CI, 0.58-0.97; P=.029).
The total years of life saved from breast cancer in the intervention group was estimated as 620, corresponding to 11.5 years saved per 1000 women invited to earlier screening.
No significant reduction was seen after more than 10 years (126 vs 255 deaths; RR, 0.98; 95% CI, 0.79-1.22; P=.86).
The results also suggest at worst modest overdiagnosis in this age group, and that any overdiagnosed cancers would otherwise be diagnosed at NHS screening from 50 years of age.
Lead researcher Professor Stephen Duffy from Queen Mary University of London said: “This is a very long term follow-up of a study which confirms that screening in women under 50 can save lives. The benefit is seen mostly in the first ten years, but the reduction in mortality persists in the long term at about one life saved per thousand women screened."
“We now screen more thoroughly and with better equipment than in the 1990’s when most of the screening in this trial took place, so the benefits may be greater than we’ve seen in this study.”