Current perspectives on radiation-induced breast cancer.

PURPOSE: An approach to screening and detection of radiation-induced breast cancer is offered. Primary and secondary prevention strategies are suggested and the need for prospective clinical trials is emphasized.

METHODS: Data are reviewed from published evidence of radiation-induced breast cancer secondary to atomic bomb radiation, occupational, and therapeutic exposure, especially that incurred during successful treatment of Hodgkin's disease (HD). Preclinical studies are reviewed to explore potential risk factors.

RESULTS: Risk factors evident in the link between radiation and breast cancer include the differentiation of breast tissue as mediated by age and hormonal influence. Evidence is presented exploring the link between genetics and breast cancer, including specific genes such as the BRCA1 and BRCA2 genes, the p53 gene, the ataxia telangiectasia (AT) gene, and other nonspecific alterations in DNA repair proficiency. In light of these findings, steps toward primary prevention are discussed, including avoiding radiation exposure, genetic screening, and manipulation of the hormonal milieu. Secondary prevention may also be possible with the use of tamoxifen, low-fat diets, and/or the consumption of flaxseed.

CONCLUSION: Our current recommendations for patients irradiated before 30 years of age for Hodgkin's disease include breast self-examination (BSE) monthly, yearly mammography 8 years postirradiation, and regular physical examinations every 6 months. Given the clear link between radiation exposure and breast cancer, we strongly recommend a prospective trial randomize patients to different levels of intensity of surveillance to monitor the efficacy of such screening efforts.