Radiation induced breast cancer risk in BRCA mutation carriers from low-dose radiological exposures: a systematic review

The aim of this review paper is to clarify the radio-induced breast cancer (BC) risk in BRCA mutation carriers with a combined epidemiological and radiobiological comprehensive approach. A systematic literature search on PubMed (MEDLINE) and EMBASE was performed for articles published from January 1st, 2000 to June 15th, 2017 using dedicated key words as subject headings (MeSH) in three domains of research and evaluation: risk modeling, cohort-studies and ex-vivo radiation biology with epithelial non-tumoral human breast cells. Only eleven articles that meet the selection criteria could be retrieved. These articles are analyzed and discussed. This review, which includes all types of radiological breast exposures, shows an association between BC risk and low cumulative X-ray doses before age 30. There is no consistent data in this literature regarding the risk of BC from radiological exposure after age 30. Biological data point out strong indicators of radiation-induced genomic instability linked with carcinogenesis pathways. We conclude that the risk of radio-induced BC in BRCA mutation carriers depends on age at exposure and that repeated X-ray breast exposures such as mammography should be used very cautiously in these mutated patients.