Late toxicity is not increased in BRCA1/BRCA2 mutation carriers undergoing breast radiotherapy in the United Kingdom

Purpose: To undertake the first substantial clinical study of breast radiotherapy toxicity in BRCA1 and BRCA2 mutation carriers in the United Kingdom. Experimental Design: Acute and late radiation effects were evaluated in a retrospective study of 55 BRCA1 and BRCA2 mutation carriers treated with radiotherapy for breast cancer at four centers between 1983 and 2002. Individual matching with controls who had sporadic breast cancer was undertaken for age at diagnosis, time since completion of radiation, and treatment variables. Detailed assessments were undertaken by one examiner. Median follow-up was 6.75 years for carriers and 7.75 years for controls. Rates of late events (rib fractures, lung fibrosis, necrosis of soft tissue/bone, and pericarditis) as well as LENT-SOMA scores and clinical photography scores of breast size, shape, and skin telangiectasia were the primary end points. Results: No increase in clinically significant late toxicity was seen in the mutation carriers. Conclusions: These data add substantial weight to the evidence that the outcomes in the treated breast from radiotherapy in women with BRCA1 or BRCA2 mutations are comparable with those in women with sporadic breast cancer.