Can breast cancer be inherited?

  • Breast cancer is common with an average lifetime risk of breast cancer of 1 in 10 women .
  • The cause is mainly sporadic (random/ as a once off) influenced by environment and lifestyle.
  • In a small number of cases (5-10%) breast cancer is inherited (passed from one generation to the next).
  • Individuals from these families have an increased chance of developing cancer in their lifetime.
  • Knowing your risk of hereditary breast cancer is important for your future health as it allows access to healthcare options to reduce the impact of cancer in your life.

What is hereditary breast cancer?

  • Hereditary breast cancer is an inherited condition.
  • When present your risk of developing breast cancer and other related cancers at a young age is greater than the average person.

What is the role of genetics in hereditary breast cancer?

  • Genes carry information that defines how our bodies work, look and develop.
  • These are inherited from both parents and hence each person has two copies of each gene.
  • Faults (mutations) in certain genes can lead to an increased risk for cancer.
  • Hereditary breast cancer has been associated with mutations in one of two genes, BRCA1 or BRCA2.
  • The role of these genes is to prevent the development of cancer.
  • Mutations in these genes are inherited in an autosomal dominant manner.
  • Meaning the risk for hereditary breast cancer is 50/50 and this is the same for both males and females.
  • If you have a BRCA1 or BRCA2 mutation you have a:
  • 50 to 80% lifetime risk of developing breast cancer.
  • 60% of developing a second primary breast cancer.
  • 20% to 60% risk of developing ovarian cancer.

When should you be concerned about hereditary breast cancer?

  • A BRCA1 or BRCA2 mutation has been identified in another family member.
  • You have a personal history of breast cancer or any other associated cancer such as ovarian, melanoma, prostate cancer.
  • You have a family history of breast cancer and/or other associated cancers such as ovarian, melanoma, prostate cancer.
  • You have a family history of cancer diagnosed at an early age such as younger than 50 years for breast cancer.
  • You have a family history of unusual or rare cancers.
  • Multiple primary (first) cancers in the same individual – same or different organs.
  • Bilateral (both sides) cancers in paired organs e.g. breasts, eyes.
  • Family history of male breast cancer.
  • You are from an ethnic group known to be at risk for hereditary breast cancer such as Ashkenazi Jewish or Afrikaans.

How will genetic counselling help you if you are concerned about a hereditary breast cancer?

  • You will be given information on the role of genetics in the development of hereditary breast cancer.
  • A cancer risk model will be used to assess your risk for hereditary breast cancer in your family and used to define the risk for you and your family.
  • Your results will be used to develop a personalised plan for screening, management and genetic testing.
  • The benefits, risks and limitations of these health options will be discussed in an emotionally supportive environment to allow for optimal decision-making for the future.

What happens during a genetic counselling session?

During genetic counselling the genetic counsellor will:

  • Obtain a family and personal medical history.
  • Draw up a family tree.
  • Use the medical information and family tree to assess the risk of a hereditary cancer syndrome.
  • Discuss the cause, inheritance, your risk of a hereditary breast cancer and the likelihood of cancer in you and other of your family members.
  • Discuss genetic testing (if appropriate), preventative and screening options, including the benefits, risks and limitations.

What are the recommended screening options if you have/ are at risk for hereditary breast cancer?

  • Monthly breast self examinations from early adulthood.
  • Six monthly to annual clinical breast examinations.
  • Annual mammography or sonography or MRI from 40 years of age (or 5 years earlier than youngest age of diagnosis).

Please note that these are guidelines and may differ between specialists. The types of healthcare options/interventions and their timing will be defined by the treating specialist.

Is there genetic testing available for BRCA1 and BRCA2 genes?

  • Limited genetic testing of the BRCA1 and BRCA2 genes is available in South Africa but more comprehensive testing is available overseas.
  • Genetic testing is ideally first performed on a family member that has had a diagnosis of cancer.
  • If a mutation is identified in either the BRCA1 or BRCA2 genes then testing can be offered to other relatives.

Please note that most medical aids do not provide funding for the cost of genetic tests.

What if no gene mutation is found in the BRCA1 or BRCA2 gene?

  • If no mutation is identified but your family was assessed as being at high risk for hereditary breast cancer, then you would continue with recommended screening options as for individuals where a mutation was found.

How does knowing your risk help you?

  • Preventative and management options are based on your family history and/or BRCA1 and BRCA2 gene test result.
  • If your family is at high risk for a hereditary breast cancer accessing to preventative treatment and more intensive screening methods could substantially reduce the risk of developing cancer.
  • Your risk for hereditary breast cancer can be used to define the risk for other family members.

Need more information about hereditary breast cancer?

Please Contact Us should you need more information about hereditary breast cancer, explore your risk for hereditary breast cancer or want to make an appointment to determine whether your family is at risk for hereditary breast cancer.

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