Breast cancer screening is not without controversy
Breast cancer screening may have reduced the number of deaths from the disease by at least 30%, a study looking at one programme suggests.
The study of the East Anglia screening programme is one of the first to try to evaluate what impact the national scheme, started in 1989, has had.
The findings, published in the British Journal of Cancer, appear positive.
But one breast cancer specialist said the drop in deaths was in fact due to the way treatment has improved.
A team led by Cancer Research UK but including researchers from the Wolfson Institute of Preventive Medicine and the University of Cambridge compared the screening histories of women who had died of the disease with women who had not.
Those who had attended any screening had a 60% lower risk of death from breast cancer than those who had never been screened.
But accepting there may be "self-selection bias" - those who choose not to attend may be in poorer health to start with - they said this figure needed to be modified.
After making adjustments, they calculated that women who attended screening had at least a 30% reduction in breast cancer mortality, a figure which is consistent with randomised trials.
"This is the strongest evidence yet that screening programmes like this save lives," said Professor Stephen Duffy, Cancer Research UK's specialist in cancer screening.
"We hope to collect data from other regions in the future, allowing us to compare programmes across the UK, bringing the best practice to areas that aren't performing as well."
'Treatment not screening'
All women between the ages of 50 and 70 are currently invited to be screened every three years, using mammograms, at a cost of £75m a year.
Last month, the government announced plans to extend that age range to include women from the age of 47 up to 73.
But the programme is not without controversy. There are studies which have suggested that for every life saved, several women undergo distressing and invasive treatment they do not need as a result of mis- or overdiagnosis.
Professor Michael Baum, who has made no secret of his opposition to the NHS breast screening programme in the past, said it was treatment not screening which reduced mortality.
"The 30% figure is consistent with the drop in mortality we have seen since better treatment began in the 1980s," he said.
"If you screened 1,000 women over ten years, one life will be saved. In the meantime many women will go through the distress of false alarms. All the women I see have found the lump themselves, not as a result of screening."
Breast Cancer Care said screening and breast awareness should go hand-in-hand.
"As well as accepting invitations to regular breast screening, it is vital that women of any age are breast aware throughout their life, by being familiar with how their breasts normally look and feel so that any changes unusual for them can be picked up quickly and reported to their doctor without delay."