Breast cancer screening between the ages of 50 and 69 leads to a 40% reduction in women dying of the disease, according to a major international review.
Overall, women invited to attend mammography screening have a 23% reduction in breast cancer death compared with women not invited by routine screening programmes.
In the UK, this risk translates to around eight deaths prevented per 1,000 women regularly attending screening, the findings published in the New England Journal of Medicine said.
The review saw 29 experts from 16 countries analyse more than 50 trials and studies and conclude that screening of women aged 70 to 74 also results in an significant reduction in breast cancer mortality - more so than thought from previous research.
But evidence for the effectiveness of screening women in the younger age group of 40 to 49 was limited.
Overall, the researchers said screening detects breast cancers that would never have been diagnosed or caused harm if the women had not been screened.
Breast cancer is the most common type of cancer in the UK and in 2011, just under 50,000 women were diagnosed, the majority over 50.
The NHS breast screening programme invites all women between the ages of 50 and 70 for mammography.
Although it saves lives, screening also comes with various negative effects such as false-positive results, overdiagnosis and radiation-induced cancer, but experts said their review builds on previous evidence which suggests the potential benefits of breast screening outweigh the risks.
The research, co-ordinated by the International Agency for Research in Cancer (IARC), the World Health Organisation’s specialised cancer agency, looked at breast cancer screening on a global level, taking into account routine screening programmes where all women of a certain age are invited to attend, and opportunistic screening services, which operate in countries without a set programme.
Stephen Duffy, professor of cancer screening at Queen Mary University of London, was one of the scientists involved.
He said: "This important analysis will hopefully reassure women around the world that breast screening with mammography saves lives. The evidence proves breast screening is a vital tool in increasing early diagnosis of breast cancer and therefore reducing the number of deaths.
“Despite evidence that mammography screening is effective, we still need to carry out further research on alternative screening methods, such as the promising digital breast tomosynthesis, a newly developed form of 3D imaging which could potentially improve the accuracy of mammography in coping with more dense breast tissue.
“It is also vital we continue researching the most effective ways of screening women at high risk of breast cancer due to family history or genetic status. We need further evidence to fine-tune services offered to high-risk women in terms of different screening methods, from an earlier age and possibly at shorter intervals.”