MRI scans can vastly improve detection rates of breast cancer in the other breast for women who have been recently diagnosed with it in the first breast, a new Canadian and US study suggests.
Following the study the American Cancer Society have recommended that women with cancer in one breast should get the other breast checked with an MRI scan, and also that women at high risk of breast cancer should receive MRI scans.
The study is to be published later this week in the New England Journal of Medicine (NEJM) and was sponsored by the National Cancer Institute, one of the US government’s National Institutes for Health (NIH).
The research was conducted by the American College of Radiology Imaging Network (ACRIN) at 25 centres in Canada and the US, and involved researchers from the University of North Carolina (UNC) at Chapel Hill.
The researchers discovered that magnetic resonance imaging (MRI) detected cancer in the other breast in 3.1 per cent (30) of 969 women with a recent diagnosis of cancer in one breast. Previous mammographies (a special type of X ray) and clinical examinations had failed to detect cancer in the other breast.
NIH Director Dr Elias Zerhouni said that ten per cent of women diagnosed with cancer in one breast develop cancer in the other breast as well. “Having a better technique to find these cancers as early as possible will increase the chances of successful treatment,” he added.
This technique should also help to avoid the two rounds of surgery and possibly chemo and radiotherapy treatment that women who subsequently develop cancer in the other breast (having previously received the all clear with mammography and clinical exam) have to undergo. This way they can be treated for cancer in both breasts at the same time.
The study’s authors suggest women with high risk for breast cancer should receive MRI scans. These include women who already have the disease, those who have been recently diagnosed, and also those with a family history of breast cancer.
If an MRI of the other breast is negative, said Dr John Niederhuber, Director of the National Cancer Institute, then this can give women more confidence about opting against double mastectomy.
he authors pointed out that the purpose of the study was not to establish if MRIs are better breast cancer detectors than the X ray mammogram in women with average risk, but to find out if MRIs improve detection in the other breast of women who already have cancer in one breast.
MRI scans do not detect calcifications, one of the early signs of breast cancer, wheareas mammograms do.
Study co-author Dr Etta Pisano, a principal investigator and Kenan professor of radiology and biomedical engineering at the UNC School of Medicine said, “This study is pretty definitive evidence that the opposite breast needs to be evaluated with MRI.”
“But no one is recommending that we give up mammography. MRI screening is a very expensive tool that should be used judiciously for high risk populations. The last thing we would want is for every woman to think she should get an MRI,” added Dr Pisano.
60 per cent of the cancers detected by MRI were invasive, and could spread into the rest of the body. “Such tumours are the most important ones to find”, said Dr Pisano.
She added that the percentage of cancers found in the other breast was huge.
“If you were to screen the opposite breast with mammography in the general population, you would expect to find four to seven cancers per 1,000 patients. This study found three per 100, nearly ten times higher,” she added. Dr Pisano is director of the UNC Biomedical Research Imaging Center and a member of the UNC Lineberger Comprehensive Cancer Center.
Chair of the American Cancer Society’s Breast Cancer Advisory Group, Dr Christy Russell pointed out that the danger of using MRI is that like other screening tests it can produce false positive results, more so than mammograms. These cause enormous stress and anxiety, which in turn exacerbates health problems. It is important that women who undergo MRI scans are carefully selected, she said.
While breast cancer predominantly affects and kills women, men also get it and die from it.
The National Cancer Institute estimates that in 2007 in the US:
– 178,480 women will be diagnosed with breast cancer and 40,460 will die from it, and
– 2,030 men will be diagnosed with it, and 450 will die from it.