Diagnostic radiation may raise breast cancer risk | Cancer Kick

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Women who have a mutation in the BRCA1 or BRCA2 gene and have undergone diagnostic radiation to the chest before age 30 are more likely to develop breast cancer than those who carry the gene mutation but who have not been exposed, according to a study.

Exposure to radiation is an established risk factor for breast cancer in the general population, according to background information in the study, which appeared Sept. 6 on the website of the British Medical Journal. Some studies have suggested that women with a mutated BRCA1/2 gene may have increased radiation sensitivity because BRCA1 and BRCA2 are the genes involved in the repair of DNA breaks, which can be caused by radiation. The benefit from mammographic screening in young BRCA1/2 mutation carriers may therefore not outweigh the radiation risk.

Some countries have gone as far as recommending that women avoid mammographic screening before age 30, the researchers noted, but previous study results have been inconsistent.

Researchers from the Netherlands Cancer Institute looked at 1,993 female BRCA1/2 mutation carriers in the Netherlands, France and the United Kingdom between 2006 and 2009 to determine whether variations in DNA increase the chances of radiation-induced breast cancer risk. Follow-up ended with diagnosis of first breast cancer. All patients were 18 and older and were questioned on exposure via x-ray or mammogram, age at first exposure, number of exposures before age 20, at ages 20 to 29 and 30 to 39, and age at last exposure.

Results showed that 43% (848) of the women were diagnosed with breast cancer, 48% (926) reported ever having an x-ray and 33% (637) reported ever having a mammogram. The average age at first mammogram was 29.

A history of any exposure to diagnostic or screening radiation to the chest at ages 20 to 29 increased breast cancer risk by 43%, and any exposure before age 20 increased breast cancer risk by 62%. No association with breast cancer was apparent for exposures at ages 30 to 39.

The authors estimated that for every 100 BRCA1/2 mutation carriers age 30, nine will have developed breast cancer by age 40 and the number of cases would increase by five if all had a mammogram before age 30. The estimate ?should be interpreted with caution because there were few women with breast cancer who had had a mammogram before age 30 in the study.?

To read the study, visit www.bmj.com/content/345/bmj.e5660.

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Article source: http://news.nurse.com/article/20120915/NATIONAL02/109170024/-1/frontpage

Source: http://cancerkick.com/2012/09/15/diagnostic-radiation-may-raise-breast-cancer-risk/

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