'BRCA genes help repair DNA
damage — damage which can be caused by exposure to radiation like X-rays. Women
with faults in these genes are less able to repair damage caused by radiation,
so they are at a greater risk of developing breast cancer', said Professor
Douglas Easton, a UK Cancer Research scientist and one of the authors of the
study at the University of Cambridge.
Approximately one in
400 women carry mutations in their BRCA genes. The study, published in the
British Medical Journal, enrolled almost 2,000 women with faulty BRCA genes from
the UK, France and the Netherlands. Of these women, those who were exposed to chest
radiation before the age of 30 were found to be 43 percent more likely to develop
breast cancer, when compared to those women with BRCA mutations who were not.
The results of
the study estimated that for every 100 women with faulty BRCA genes,
nine would develop breast cancer by the time they reached the age of 40. Researchers
then projected that if 100 women with faulty BRCA genes were exposed to radiation from one mammogram
before the age of 30, the number who would go on to develop breast cancer would increase to 14.
Dr Anouk Pijpe,
one of the authors of the study from the Netherlands
Cancer Institute, said: 'We believe
countries who use mammograms in women under 30 should reconsider their
guidelines. It may be possible to reduce the risk of breast cancer in
(high-risk) women by using MRIs [magnetic resonance imaging], so we believe
physicians and patients should consider that'. MRIs, unlike traditional mammograms, do not use
radiation to scan the breast tissue.
Dr Julie Sharp, senior science information
manager at Cancer Research UK, said: 'In the UK younger women are already
screened using MRI scans rather than mammograms to avoid these risks — but this
isn't the case in all countries yet'.