By David Liu, PHD

Saturday Oct 6, 2012 (foodconsumer.org) -- A new study in British Medical Journal found evidence to suggest that exposure to diagnostic radiation before age 30 can drastically increase risk of breast cancer in women with BRCA1/2 mutations.

Ionizing radiation, x-ray in the case, used in medical diagnostics and treatment is a known carcinogen, according to the National Toxicology Program.  

In women with BRCA1/2 mutations, any exposure to diagnostic radiation before age 30 was found correlated with a 90 percent increased risk of developing breast cancer.  And the increase was dose-responsive, higher doses leading to a higher risk.

Specifically, the risk by quarter of estimated cumulative dose, smaller than 0.0020 Gy, greater or equal to 0.0025 to 0.0065 Gy, greater or equal to 0.006 to 0.0173 Gy and greater or equal to 0.017 gy was increased by 63, 78, 75 and 284 percent, respectively.

Exposure to x-ray- based mammography before age 30 was also correlated with a 43 percent increased risk of breast cancer.

Family history of breast cancer did not change the associations.

The study was based on data 1993 female carriers of BRCA1/2 mutations recruited in 2006 to 2009 for three nationwide studies, GENEPSO, EMBRACE, HEBON, in France, United Kingdom, and the Netherlands.

The researchers concluded "In this large European study among carriers of BRCA1/2 mutations, exposure to diagnostic radiation before age 30 was associated with an increased risk of breast cancer at dose levels considerably lower than those at which increases have been found in other cohorts exposed to radiation."

"The results of this study support the use of non-ionizing radiation imaging techniques (such as magnetic resonance imaging) as the main tool for surveillance in young women with BRCA1/2 mutations."

Mammography is one screening tool that some experts have said can cause breast cancer.  The study findings are inconsistent with what an authoritative organization suggests - women should avoid medical radiation in addition to avoiding hormone therapy.