Are siblings at risk if parents have a BRCA2 mutation?

Question

Hello doctor,

My mom recently received her BRCA genetic test results, and I am really worried. She was diagnosed with stage 2 invasive lobular breast cancer last year, with a 3.2 cm tumor (grade 2) and clear surgical margins. Now, the genetic test shows she has a BRCA2 mutation.

What does this mean for my sisters and me?
Should we get tested?
What are our risks?

Before surgery, her mammogram showed an irregular mass with microcalcifications, and her Oncotype DX score was 23, which suggested chemotherapy. I want to fully understand this to protect my family.

Please help.

Thank you in advance.

Answer 1

Hi,

Welcome to icliniq.com.

I read your query and can understand your concern.

To provide you with a clear understanding, I need to know the status of your mom’s estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) receptors and whether the lymph nodes are involved.

BRCA1 (breast cancer gene 1) mutations are associated with a 50 to 85 percent lifetime risk of developing breast cancer and up to a 20 to 50 percent risk of ovarian cancer. BRCA2 (breast cancer gene 2) mutations are linked to a 50 to 60 percent risk of breast cancer and a 20 percent risk of ovarian cancer. Additionally, BRCA2 mutations can increase the risk of cancers of the gall bladder, colon, bile duct, and stomach.

Women with a BRCA (breast cancer gene) mutation may consider a bilateral risk-reducing mastectomy with immediate breast reconstruction, which can reduce the risk of breast cancer by 90 percent. Chemoprophylaxis with Tamoxifen or Anastrozole may reduce the risk by 50 percent. Premenopausal women who have completed their family may also be offered a bilateral salpingo-oophorectomy around the age of 40.

Since your mother has been diagnosed with a BRCA2 mutation, these options should be considered if she has completed her family.

For you and your sister, regular screening is crucial to detecting the disease at an early stage. Genetic breast cancer can be inherited, so family screening is important. This includes clinical breast exams every three months for two years, followed by every six months for three years, and annual mammograms thereafter.

I hope this helps.

Kindly revert so I can assist you further.

Thank you.