A 31-year-old woman was referred by the Clinical Genetics Department for discussion of bilateral prophylactic mastectomy. The patient's mother and maternal grandmother both developed breast cancer at 33 and 39 years of age, respectively, and the patient herself was increasingly conscious that she was approaching this age. In addition, to these two relatives, the patient's family history included two maternal great aunts with postmenopausal disease and a maternal grandfather with prostate cancer. Though familial cancer history was incompletely documented, the patients estimated lifetime risk for development of breast cancer was 80% to 85%. There was a high probability of either BRCA-1 or BRCA-2 mutation carriage and genetic testing of the patient's mother and sister was pending at the time of referral. In particular, the patient understood that in the absence of any gene mutation, her risk of developing breast cancer was comparable to an age-matched population. She was keen to pursue prophylactic surgery without information from formal genetic testing (though both the patient and her sister were subsequently confirmed to carry a BRCA-2 gene mutation). This was a carefully considered decision by the patient who had a very balanced and informed point of view. She was a single parent and rather preoccupied with the risk of developing breast cancer and the possible impact on her child. The patient wished to minimize her risk and was provided with quantitative
information on risk reduction from prophylactic surgery.