Genetic Predisposition to Breast Cancer: when public awareness demands clarity

By Dr. Luis Costa, Director of Oncology at Santa Maria Hospital, Lisbon.

 Ever since last May, a great deal of attention has been focused on news that the actress Angelina Jolie underwent a preventive bilateral mastectomy after learning that she was a carrier of a pathogenic gene mutation (1) known to be responsible for a higher incidence of breast and/or ovarian cancer.

Among the many media messages emerging from Jolie’s revelation was that carriers of such a mutation should consider preventive surgery and that non-carriers could rest easy that they were in a lower risk category. While these messages have opened up useful opportunities for dialogue between a woman and her doctor, the truth behind genetic testing is much more complex. 

Women who have a heritable BRAC1 or BRAC2 gene mutation such as Jolie’s bear the same characteristic or genetic defect that gives them a higher genetic susceptibility to cancer. Research into these mutations has been of incredible valuable in identifying women who may benefit from certain preventive measures. Indeed, once found to be carriers, patients’ relatives can be also screened and can then make informed decisions as to precautionary strategies going forward. Yet not only does a genetic predisposition for breast cancer represent only an average of 5% of all cases but the cumulative lifetime risk of cancer varies between 15% and Read more