The risk for a new cancer in the unaffected breast substantially increases in women diagnosed with unilateral, hereditary (non-BRCA) breast cancer, according to a new study.
Published in the March 15, 2006 issue of CANCER, a peer-reviewed journal of the American Cancer Society, the study reveals women under 50 diagnosed with hereditary (non-BRCA) breast cancer are at significantly greater risk for developing cancer in the other breast, also known as contralateral breast cancer (CBC). Adjuvant hormonal therapy, however, reduces CBC risk.
Women with hereditary (non-BRCA) breast cancer are estimated to be at up to six times greater risk of developing a second primary malignancy in the other breast than the general population is of developing primary breast cancer. Young age at first diagnosis, family history of breast cancer, and confirmed BRCA1 or BRCA2 gene mutations are the primary risk factors for CBC. However, the contribution of non-BRCA hereditary cancers to the risk of CBCs is poorly understood.
Led by Katarina Shahedi, M.D. of the Umee University and colleagues at the Karolinska Institute in Stockholm, Sweden, researchers reviewed data from 120 families and 204 women with unilateral breast cancer and a family history of breast cancer but no BRCA mutations to better characterize the CBC risk for these women.