New Guidelines on Managing Hereditary Breast Cancer

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Three professional organizations have put out guidelines on how to treat and manage breast cancer in people with a genetic mutation linked to a higher risk of the disease.

The guidelines were published online on April 3, 2020, by the Journal of Clinical Oncology. Read “Management of Hereditary Breast Cancer: American Society of Clinical Oncology, American Society for Radiation Oncology, and Society of Surgical Oncology Guideline.”

Each of the societies are national organizations made up of medical oncologists, radiation oncologists, cancer surgeons, and other cancer care providers. These expert guidelines give doctors recommendations that are supported by much credible research and experience.

Genetic mutations linked to hereditary breast cancer

About 5% to 10% of breast cancers are thought to be hereditary, meaning the cancer is linked to germline mutations passed from parent to child.

Three of the most well-known genes that can mutate and raise the risk of breast and/or ovarian cancer are BRCA1, BRCA2, and PALB2. Women who inherit a mutation, or abnormal change, in any of these genes — from their mothers or their fathers — have a much higher-than-average risk of developing breast cancer and/or ovarian cancer. Abnormal PALB2 genes are suspected to raise the risk of ovarian cancer, but larger studies need to confirm that risk. Men with these mutations have an increased risk of breast cancer, especially if the BRCA2 gene is affected, and possibly of prostate cancer. Many inherited cases of breast cancer have been associated with mutations in these three genes.

Inherited mutations in other genes are also associated with breast cancer. These abnormal gene changes are much less common than BRCA1 and BRCA2 mutations, which themselves are fairly uncommon. Also, most of them don't seem to increase breast cancer risk as much as abnormal BRCA1 and BRCA2 genes. Still, because these genetic mutations are rare, they haven't been studied as much as the BRCA genes.

Genetic mutations estimated to increase breast cancer risk by more than 50%:

  • PALB2
  • PTEN
  • TP53

Genetic mutations estimated to increase breast cancer risk by 25% to more than 50%:

  • ATM
  • CDH1

Genetic mutations estimated to increase breast cancer risk by 25% to 50%:

  • CHEK2
  • NBN
  • NF1
  • STK11

You are much more likely to have a genetic mutation linked to breast cancer if:

  • You have blood relatives (grandmothers, mother, sisters, aunts) on either your mother's or father's side of the family who had breast cancer diagnosed before age 50.
  • There is both breast and ovarian cancer on the same side of the family or in a single individual.
  • You have a relative(s) with triple-negative breast cancer.
  • There are other cancers in your family in addition to breast, such as prostate, melanoma, pancreatic, stomach, uterine, thyroid, colon, and/or sarcoma.
  • Women in your family have had cancer in both breasts.
  • You are of Ashkenazi Jewish (Eastern European) heritage.
  • You are African American and have been diagnosed with breast cancer at age 35 or younger.
  • A man in your family has had breast cancer.
  • There is a known breast cancer gene mutation in your family.

Guideline recommendations

The guidelines recommend:

  • Having a BRCA1 or BRCA2 mutation does not mean that a person can’t have a lumpectomy.
  • People with any of the genetic mutations linked to breast cancer have a much higher risk of being diagnosed with a new cancer in the opposite breast, so doctors should discuss whether contralateral prophylactic mastectomy — removing the other, healthy breast — is a good option to reduce that risk, especially with younger women.
  • People with a BRCA1 or BRCA2 mutation who do not have a double mastectomy should have screening with both an annual mammogram and an annual MRI. In most cases, you would have one screening and then the other 6 months later.
  • Women who have a mutation in the ATM, CDH1, CHEK2, NBN, NF1, or STK11 genes are eligible for lumpectomy. Doctors should discuss the specific risk of breast cancer in the opposite breast based on the genetic mutation with these women.
  • Women who have a mutation in the ATM, CDH1, CHEK2, NBN, NF1, or STK11 genes who do not have a double mastectomy should have screening with both an annual mammogram and an annual MRI. In most cases, you would have one screening and then the other 6 months later.
  • For women with any of the genetic mutations linked to breast cancer, nipple-sparing mastectomy is a reasonable option.
  • Radiation therapy after lumpectomy or mastectomy should not be withheld because of genetic mutation status, except for women with a TP53 mutation. Research suggests that radiation therapy dramatically increases the risk of a second cancer in people with a TP53 mutation. So women with a TP53 mutation should have mastectomy rather than lumpectomy.
  • For people with a BRCA1 or BRCA2 mutation who have been diagnosed with metastatic breast cancer, platinum chemotherapy is preferred over taxane chemotherapy, as long as the person has not been treated with platinum chemotherapy before. Carboplatin is the only platinum chemotherapy approved to treat breast cancer. Abraxane (chemical name: albumin-bound or nab-paclitaxel), Taxol (chemical name: paclitaxel), and Taxotere (chemical name: docetaxel) are taxane chemotherapy medicines used to treat breast cancer.
  • For people with a BRCA1 or BRCA2 mutation diagnosed with non-metastatic breast cancer who will be treated with chemotherapy before surgery, research doesn’t support adding platinum chemotherapy to taxane-based and anthracycline-based chemotherapy. Adriamycin (chemical name: doxorubicin) is the most well-known anthracycline chemotherapy.
  • People with a BRCA1 or BRCA2 mutation diagnosed with metastatic HER2-negative breast cancer should be treated with Lynparza (chemical name: olaparib) or Talzenna (chemical name: talazoparib) instead of chemotherapy.

What this means for you

If you’ve been diagnosed with breast cancer and know you have a genetic mutation linked to a higher risk of the disease, it makes sense to talk to your doctor about these guidelines and how they might affect your treatment plans.

Still, research suggests that many people with mutations linked to breast cancer are not having genetic testing because they do not meet national testing guidelines. In February 2019, the American Society of Breast Surgeons issued guidelines saying that genetic testing should be made available to everyone who has been diagnosed with breast cancer.

If you’ve been diagnosed with breast cancer, you may want to talk to your doctor or a licensed certified genetic counselor about your diagnosis and your family history and ask if having a multigene panel test makes sense for you. A licensed certified genetic counselor or your doctor can help you understand the test and accurately interpret the results.

For more information on genetic testing, including types of genetic tests and how results are reported, visit the Breastcancer.org Genetic Testing pages.

For more information on genes and genetic mutations linked to breast cancer, as well as all the risk-lowering steps you can take if you have a genetic mutation, visit the Breast Cancer Risk Factors: Genetics page in the Breastcancer.org Lower Your Risk section.

To discuss being at high risk for breast cancer with other people, join the Breastcancer.org Discussion Board forum High Risk for Breast Cancer. If you've tested positive for a mutation linked to breast cancer and would like to talk about this with others who have also tested positive, join the forum Positive Genetic Test Results.

Written by: Jamie DePolo, senior editor

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