Sara T* recently moved back to the area to be closer to her family. The 34-year-old patient visited our office to discuss the benefits and potential risks of genetic counseling. She explained that her aunt had just died at age 64 of ovarian cancer. Also, her maternal cousin had been diagnosed at age 42 with breast cancer, and her maternal grandmother had died at age 45 of an unknown “female cancer.” She was scared to find out if she had high-risk genes because she felt it would change her life forever. However, if she ignored the issue, she thought she might worry too much.
We discussed the implications of a positive result, such as having to live with the knowledge and to make decisions about potential screening and risk-reducing surgery. On the other hand, not knowing could allow for the undetected growth of cancer that might otherwise be mitigated to some degree if she knew her risk status and pursued an aggressive screening program.
We worked with Ms. T to map out her next steps.
*The patient’s name has been changed to protect her identity.
Breast cancer is the most commonly diagnosed cancer in women worldwide, representing nearly one-quarter of all female cancer diagnoses in 2018.1 It is the second-leading cause of cancer death in women in developed nations and the leading cause of cancer death in women in developing nations.1 In the United States, 1 in 8 women will develop breast cancer in her lifetime.2 By comparison, the rate of ovarian cancer is much lower, with a lifetime prevalence of 1 in 70 to 80 women.3,4 Although ovarian cancer is less common than breast cancer, its associated mortality is high, and most cases are discovered at advanced stages.
The outsized threat of BRCA mutations. It is estimated that 5% to 10% of all breast cancers are hereditary, with 80% of these attributable to BRCA1 (45%) and BRCA2 (35%).5 These autosomal dominant mutations occur at the germline level, within the egg or sperm, and are therefore incorporated into the DNA of every cell and passed from one generation to the next. Families with BRCA mutations have much higher lifetime rates of cancer. The lifetime risk of breast cancer due to BRCA mutations is estimated at > 80% (BRCA1) and 45% (BRCA2).5BRCA mutations account for between 10% and 18% of all ovarian cancers6 and convey a lifetime risk of 40% (BRCA1) and 15% (BRCA2) to carriers.5
Male BRCA carriers have a lifetime breast cancer risk of 1% to 5% with BRCA1 and 5% to 10% with BRCA2,7,8 compared with about 1:1000 lifetime incidence in the unselected male population. Male carriers are also at risk for more aggressive prostate cancers.7,8
Continue to: Certain populatiosn carry undue burden of BRCA-related disease