Screening cuts risk of breast cancer death almost in half

Women who undergo mammography screening reduce their risk of dying from breast cancer by 40 per cent, an international study published in the United States showed.

Researchers reported that women aged 50 to 69 who received screening were 40 per cent less likely to succumb to the disease compared to women who were not screened.

Simply inviting a woman to undergo a mammography reduced her risk of death from breast cancer by 23 per cent, the researchers said in a study in the New England Journal of Medicine Wednesday.

Not all women act on the invitation, however.

"This important analysis will hopefully reassure women around the world that breast screening with mammography saves lives," said co-author Stephen Duffy of Queen Mary University of London.

"The evidence proves breast screening is a vital tool in increasing early diagnosis of breast cancer and therefore reducing the number of deaths," he added.

The study was conducted by experts from 16 countries, who evaluated different methods of breast cancer detection across 11 controlled clinical trials and 40 observational studies.

The report corroborates previous research findings that women in the 50-69 age range benefit most from breast cancer screening. But it also pointed to studies indicating women aged between 70 and 74 also stand to gain from mammography.

However, there was "limited evidence" to support screening women in their 40s, the researchers found.

"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,'" Duffy said.

The new form of 3D imaging could improve mammography accuracy in dealing with dense breast tissue, he said.

The study also shows that the benefits of mammography outweigh the risks, which include false-positive results, overdiagnosis and possibly radiation-induced cancer.

Breast cancer is "the most frequently diagnosed cancer in women worldwide," Queen Mary University said in a press release.

It is the second-largest cause of cancer deaths in developed countries and the first in low- and middle-income countries, it said.

Breast cancer caused 521,000 deaths worldwide in 2012, according to the latest figures from the World Health Organization.