Among women with a BRCA1 or BRCA2 gene mutation, chest X-rays appear to increase the risk of developing breast cancer, particularly among women who receive chest X-rays at a young age. These results were published in the Journal of Clinical Oncology.
Inherited mutations in two genes-BRCA1 and BRCA2-have been found to greatly increase the lifetime risk of developing breast and ovarian cancer. Alterations in these genes can be passed down through either the mother’s or the father’s side of the family.
X-rays involve exposure to low doses of ionizing radiation, which may cause damage to DNA. Because the BRCA1 and BRCA2 genes play a role in repairing DNA damage, women with mutations in these genes may be more susceptible to the damaging effects of radiation.
To explore the relationship between chest X-rays (not including mammograms) and breast cancer among women with BRCA1 or BRCA2 mutations, researchers in Europe and Canada conducted a study among 1,601 women. Three-quarters of the study participants had a BRCA1 mutation and one-quarter had a BRCA2 mutation.
- Women who had ever had a chest X-ray had a 54% increased risk of breast cancer.
- The age at which a woman received a chest X-ray, as well as the number of chest X-rays she received, influenced the degree to which her risk of breast cancer was increased: risk was increased to a greater extent if a woman had received a chest X-ray before the age of 20 years, or if she had received more than four chest X-rays either before or after the age of 20.
The researchers conclude that exposure to ionizing radiation from chest X-rays may increase the risk of breast cancer among women who carry a BRCA1 or BRCA2 gene mutation. Receipt of a chest X-ray before the age of 20 and receipt of a greater number of chest X-rays were linked with the greatest increase in risk.
The researchers note that confirmation of these results in other studies will be necessary before definitive recommendations can be made about the use of X-ray imaging in young women with BRCA1 or BRCA2 mutations.
Reference: Andreu N, Easton DF, Chang-Claude J et al. Effect of Chest X-rays on the Risk of Breast Cancer Among BRCA1/2 Mutation Carriers in the International BRCA1/2 Carrier Cohort Study. Journal of Clinical Oncology. Early Online Publication June 26, 2006.