Women at high risk of breast cancer should be cautious about undergoing mammography or other chest x-ray studies before the age of 30 due to the risk that radiation exposure might trigger cancer, according to research presented at last week's RSNA meeting in Chicago.
However, other scientists at the presentation cautioned that the proven ability of mammography to find early cancers in these women may strongly outweigh the possible negative effects of the x-ray procedures.
"For women at high risk for breast cancer -- those with high-risk mutations or a family history of breast cancer -- screening is very important, but a careful approach should be taken when considering mammography for screening young women, particularly those under the age of 30," said Marijke Jansen-van der Weide, Ph.D., an epidemiologist at the University Medical Center Groningen in the Netherlands.
"Our study indicates that low-dose radiation increases breast cancer risk of high-risk women when they are exposed to radiation at an early age, and when they are frequently exposed," said Jansen-van der Weide. "Young high-risk women should weigh benefits and risks together with their doctors."
She suggested that instead of undergoing x-ray mammography, breast MRI might be an alternative screening strategy.
In a meta-analysis of six studies involving 9,420 women with breast cancer, researchers found that women who undergo early mammography or receive chest x-rays are 1.5 times more likely to be diagnosed with breast cancer -- usually in their 40s -- than similar high-risk women who do not have the screening examinations, although that figure failed to reach statistical significance.
Jansen-van der Weide also noted:
- Among the 5,099 women with more than five x-ray exposures, high-risk women had 2.5 times the chance of developing breast cancer when compared with women in the general population.
- Among the 3,428 women at high risk who underwent x-ray procedures before they were 20 years of age, there was a 2.5 times greater chance of developing breast cancer.
- Having x-ray procedures after 20 years of age among the 5,142 women who met that criteria in the study indicated an increased risk of 1.8 times the control group, but that difference failed to reach statistical significance.
"The benefits of screening mammographies more than balances these figures," said Dr. Stephen Feig, professor of radiology at the University of California, Irvine and a spokesperson for RSNA, who commented on the study at a press conference.
The study is fraught with limitations, including its retrospective nature, which did not permit a good understanding of radiation dose, he said.
By Ed Susman
AuntMinnie.com contributing writer
December 11, 2009
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