A 51-Year-Old Cook Comes to Your Office for Consultation

A 51-year-old cook comes to your office for consultation. She recently found out that her 44- year-old sister with premenopausal breast cancer is positive for the BRCA1 gene. Your patient has been doing research on the Internet and saw that her chance of having also inherited the BRCA1 gene is 50%. She is interested in knowing what her risk of developing breast cancer would be if she were positive for the gene. She denies any lumps in her breasts and has had normal mammograms. She has had no weight loss, fever, or night sweats. Her mother is healthy and her father has prostate cancer. Two of her paternal aunts died of breast cancer. She is married. She denies using tobacco or illegal drugs and rarely drinks alcohol. Her breast and axilla examinations are unremarkable. At her age, what is her risk of getting breast cancer if she has the BRCA1 gene?

A) 10%
B) 50%
C) 80%