Researchers report that exposure to chest X-rays has a “relatively large effect” on breast cancer risk in women who are carriers of BRCA mutations, which increase their susceptibility to breast cancer.

Studies have shown that young girls who receive repeated X-rays for assessment of curvature of the spine have an increased risk of breast cancer.

Dr. David Goldgar of Case Western Reserve University in Cleveland, Ohio, and colleagues evaluated data on 1601 women who were either BRCA1 or BRCA2 mutation carriers and were exposed to routine, occasional and conventional chest X-rays, to assess their risk of breast cancer.

These women already have a high risk of breast cancer even without the possible extra risk conferred by chest X-rays.

The investigators found that any reported exposure to chest X-rays was associated with a 54 percent increase in the chance of developing breast cancer.

Women 40 years old or younger had an even higher risk of breast cancer after chest X-ray exposure with an increase of 97 percent. BRCA1/2 mutation carriers exposed to chest X-rays before age 20 had a more than 4-fold higher risk, the researchers report in the Journal of Clinical Oncology.

The researchers say a careful analysis of the risks and benefits of chest X-rays in young women with BRCA1/2 mutations is needed.

SOURCE: Journal of Clinical Oncology, July 20, 2006.