All women should be screened for breast cancer from the age of 40, leading doctors say.
They believe starting the routine X-rays ten years earlier than currently recommended would save thousands of lives a year.
Regular mammograms from 40 would also spare many women the trauma of having a diseased breast removed, said Professor Kefah Mokbel, a consultant plastic surgeon.
‘In my opinion, the evidence against screening in this age group is dead,’ he added.
‘The evidence is accumulating and is overwhelming and it is becoming negligent to even debate about it. We should just recommend it.’
Tumours in younger women are more likely to grow and spread quickly, making the disease the most common cause of death among women aged 35 to 54.
The professor, of the London Breast Institute and the city’s St George’s Hospital, spoke out after analysing records of almost 1,000 women diagnosed with breast cancer.
Although the disease is often thought to strike in old age, some 40 per cent of the women in the study were under 50. More than 150 women had their cancer treated at the institute, a private clinic, and 42 had previously had mammograms.
In those who had annual mammograms, the tumours were smaller and less likely to have multiple locations.
These women were also less than half as likely to need a mastectomy to keep the cancer at bay, the Radiological Society of North America’s annual conference heard.
Although the study did not look at the impact on survival, previous research has found mammograms from 40 cut the odds of dying from breast cancer by at least a quarter.
Concern about the cost of mammograms and their effectiveness in the young means British women are only entitled to free screening from 50.
Professor Mokbel agrees they are of little benefit before 40. But he believes screening should be available to all women from then.
‘The important thing about this study is that it shows that early detection leads to smaller tumour size and, very importantly, it reduces the chance of a mastectomy by more than 50 per cent.’
Lead researcher Dr Nicholas Perry, a breast radiologist, said: ‘The results of this study support the importance of regular screening in the 40-50 age group.’
In Britain, there are already plans to screen women from 47. Those with a family history of the disease are advised to start at 40. But some say the benefits of starting earlier are not convincing and false positives lead to unnecessary treatment.
Professor Julietta Patnick, of the NHS’s cancer screening programme, said the study was small and larger studies had failed to find any benefit of screening earlier.