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Genetic Testing For Hereditary Breast Cancer

Why is it concerning?

  • An estimated annual incidence of new cases of breast cancer is 1.5 lacs
  • Out of this, 10-12 thousand are hereditary or inherited cancers which are actually preventable cancer.
  • There is increased incidences in younger age groups(<35years)
  • Associated with more aggressive variants like Triple Negative (ER/PR/HER2neu negative)

What are the genes associated with breast cancer?

  • BRCA 1 gene and BRCA 2 gene are associated with hereditary breast cancer and ovarian cancer.

 Who should take this test?

  • Those who have family member with breast, ovarian or peritoneal cancer be evaluated to see, if they have a family history that is associated with an increased risk.
  • GENETIC TESTING SHOULD ONLY BE DONE IN THE SETTING OF PRE AND POST TEST GENETIC COUNSELLING,
  • It should include discussion regarding possible risks and benefits of cancer early detection and prevention modalities.
  • How is the test performed?
  • Test is performed on blood and/or saliva sample.
  • DNA extracted from sample is tested for mutation in specific genes.

What does a positive result imply?

  • BRCA1 or BRCA2 positive implies to an increased risk of developing breast or ovarian cancers.
  • However, a positive test result cannot tell whether or when an individual will actually develop cancer.
  • Both men and women, who inherit a harmful BRCA1or BRCA2 mutation, whether or not they develop cancer themselves, may pass the mutation on to their sons and daughters.

Each child has a 50 percent chance of inheriting a parent’s mutation.

  • Those with positive result should consult doctor immediately for their prevention options.

 What does a negative result imply?

  • Negative result implies to no mutation identified which suggests no increase in cancer risk above general population.

What does an ambiguous or variant of unknown significance (VUS) imply?

  • Sometimes, a genetic test finds a change in BRCA1or BRCA2, that has not been previously associated with cancer-“variant of uncertain significance”(VUS)
  • Because it isn’t known, whether this specific gene change affects a person’s risk of developing cancer.
  • Testing from a lab with strong database might reduce chances of getting an ambiguous result.

What are the prevention options for BRCA positive individuals?

  • Prophylactic surgery(bilateral mastectomy/oopherectomy)
  • Chemoprevention or hormonal therapy
  • Surveillance