OnMedica – News – Breast cancer screening linked to substantial lower risk of death

Women who attend breast screening have 60% lower risk of breast cancer death in first 10 years

Women who take part in breast screening have a significantly greater benefit from treatments than those who are not screened, according to a study* of more than 50,000 women published in Cancer.

The study, which was funded by the American Cancer Society and used data on women in Sweden, found that women who chose to participate in an organised breast cancer screening programme had a 60% lower risk of dying from breast cancer within 10 years after diagnosis, and a 47% lower risk of dying from breast cancer within 20 years after diagnosis.

The study involved 52,438 women aged 40 to 69 years in the county of Dalarna, Sweden, during 39 years of the screening era (1977-2015). All patients received stage-specific treatment according to the latest national guidelines, irrespective of the mode of detection.

The annual incidence of breast cancer was calculated along with the annual incidence of breast cancers that were fatal within 10 and within 11 to 20 years of diagnosis among women aged 40 to 69 years who either did or did not participate in mammography screening during the 39‐year period (1977‐2015).

The results showed that women who chose to participate in an organised breast cancer screening programme had a 60% lower risk of dying from breast cancer within 10 years after diagnosis (relative risk, 0.40; 95% confidence interval, 0.34‐0.48) and a 47% lower risk of dying from breast cancer within 20 years after diagnosis (relative risk, 0.53; 95% confidence interval, 0.44‐0.63) compared with the corresponding risks for non-participants.

The researchers said that this benefit occurs because screening detects cancers at an earlier stage, meaning that they respond much better to treatment.

Senior author Professor Stephen Duffy from Queen Mary University of London said: “Recent improvements in treatments have led to reduced deaths from breast cancer. However, these new results demonstrate the vital role that screening also has to play, giving women a much greater benefit from modern treatments. We need to ensure that participation in breast screening programmes improves, especially in socio-economically deprived areas.”

In the UK, mammography screening is offered to all women aged 50-70 through the NHS Breast Screening Programme, with participation rates averaging more than 70% but varying dramatically across the country, with lower rates in poorer, inner-city areas.

* Tabár L, et al. The incidence of fatal breast cancer measures the increased effectiveness of therapy in women participating in mammography screening. Cancer, published online 8 November 2018.