Mammograms may boost breast cancer risk in women with faulty gene
Radiation from mammograms may be harmful to women with mutation that makes them vulnerable to breast cancer'We believe countries who use mammograms in women under 30 should reconsider their guidelines', say experts
16:01 GMT, 7 September 2012
Mammograms aimed at finding breast cancer might actually raise the chances of developing it in some young women, a study suggests.
Researchers think the added radiation from the tests may be especially harmful to women who carry mutated genes that put them at higher risk for the disease.
They suggested that women with the mutated BRCA1 or BRCA2 genes should be screened with an MRI instead as this does not involve radiation.
Screening: Mammograms use radiation but are considered safe for older women with an average risk of breast cancer
Around one in 400 women have the
BRCA1 and BRCA1 gene abnormalities which gives them a five-fold risk of
developing breast cancer.
been proven to save lives and are clearly beneficial for women aged 50
and over who have an average risk of breast cancer. However, they are not advised for women at high risk of the disease.
Some studies have suggested women with the genetic mutations could be more sensitive to radiation because the genes are involved in fixing DNA problems. If those genes are damaged by radiation, they may not be able to repair DNA properly, raising the cancer risk.
In several European countries including Britain, the Netherlands and Spain, doctors already advise women with BRCA mutations to get MRIs instead of mammograms before the age of 30.
In the U.S., there is no specific advice from a leading task force of government advisers, but the American Cancer Society recommends yearly mammograms and MRIs from age 30 for women with BRCA gene mutations.
In the BMJ study, European researchers followed nearly 2,000 women over 18 with one of the gene mutations in Britain, France and the Netherlands.
Participants reported their previous chest X-rays and mammograms, including the age of their first screening and the number of procedures.
About 850 women were later diagnosed with breast cancer. Roughly half of them had X-rays while one third had at least one mammogram, at an average age of 29.
The researchers did not have a breakdown of how many women were exposed to chest radiation before age 30 but estimated that for every 100 women aged 30 with a gene mutation, nine will develop breast cancer by age 40.
They projected the number of cases would increase by five if all of them had one mammogram before age 30. But they cautioned their results should be interpreted with caution because most women didn't have a mammogram before 30.
Researchers suggest women having breast screening when under the age of 30 should have MRI scans instead of mammograms
Researchers found women with a history of chest radiation in their 20s had a 43 per cent increased relative risk of breast cancer compared to women who had no chest radiation at that age. Any exposure before age 20 seemed to raise the risk by 62 per cent. Radiation after age 30 did not seem to affect breast cancer risk.
'We believe countries who use mammograms in women under 30 should reconsider their guidelines,' said Anouk Pijpe of the Netherlands Cancer Institute, one of the study authors.
'It may be possible to reduce the risk of breast cancer in (high-risk) women by using MRIs, so we believe physicians and patients should consider that.'
The study was paid for by European cancer groups.
Dr Len Lichtenfeld from the American Cancer
Society said the study wouldn't immediately change their advice but said concerned women should talk to their doctor about their options.
'It's not possible today to make a blanket statement about what women (with the gene mutations) should do, but physicians and patients need to weigh the risks and benefits carefully,' he said.
He also warned that women who need scans involving radiation shouldn't avoid them because of breast cancer fears.
'No one should think that they should never get an X-ray because they have the BRCA1 or 2 gene mutations,' he said.
'Just be careful that the X-rays you get are really the ones that you need.'