Sporadic, Familial and Hereditary Breast Cancer Definitions

This is in continuation to my previous post ‘Criteria for Genetic Testing in Breast Cancer’. It is important for both patients and healthcare professionals to understand these definitions and their implications.

Sporadic Breast Cancer

Sporadic breast cancer is breast cancer with no other family history of breast carcinoma through two generations including siblings, offspring, parents, and both maternal and paternal aunts, uncles, and grandparents.

These patients do not require genetic testing for BRCA genes and risk-reduction procedures.

Familial Breast Cancer

Familial breast cancer is breast cancer with a family history of one or more first or second-degree relatives with breast cancer that does not fit the hereditary breast cancer definition given later. It is important to note that a patient with one or more first degree relatives with breast cancer in this familial breast cancer category has a substantial excess lifetime risk of breast cancer when compared with patients in the general population, who do not have affected first-degree relatives. A study found that risk ratios for breast cancer increased with increasing number of first-degree relatives involved (1.80, 2.93, and 3.90, respectively, for one, two, and three first-degree relatives).

As yet, genetic and environmental causes of familial (as opposed to hereditary) cancer are incompletely described. Some cases that demonstrate a familial pattern are found on germline testing to have BRCA1 or BRCA2 mutations, and it is difficult to know exactly where to set the threshold for genetic testing. However, quantitative risk assessment of breast cancer is extremely useful for the familial category of at-risk women and guides medical decision-making about chemoprevention, high-risk surveillance using breast magnetic resonance imaging (MRI), and prophylactic mastectomy.

Patients with increased risk should undergo the BRCA test and if they test positive, they should be counselled about risk reduction techniques.

Hereditary Breast Cancer

Hereditary breast cancer is characterized by a significantly earlier age of onset of breast cancer (before 45 years of age), bilateral breast cancer, a greater frequency of multiple primary cancers such as cancers of the breast and ovary in the HBOC syndrome(Hereditary Breast and Ovarian Cancer Syndrome), and an autosomal dominant inheritance pattern for cancer susceptibility (multiple family members with breast or ovarian cancer).

These patients should undergo BRCA testing and should be counselled about the various risk reduction techniques (which I will be discussing in my next post).

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Criteria for Genetic Testing in Breast Cancer

The recent news of Angelina Jolie’s prophylactic mastectomies has created a lot of anxiety and confusion in the minds of young ladies. Ever since the news hit the media, we are getting 2-3 queries each day regarding genetic testing and risk reduction surgery. I will try to address the whole issue in a few blog posts. In this post, I am highlighting the indications for genetic testing (BRCA 1 & 2).

Before I enumerate the various indications, I would like to clarify a couple of points.

  • Not all women require genetic testing. Only those who meet one or more of the criteria highlighted below are candidates for genetic testing.
  • Even those who test positive for the gene, require extensive counselling before they adopt any risk reduction technique.

The criteria for genetic testing are:

  • Member of a family with a known mutation in breast cancer susceptibility gene.
  • Member of a family with two or more breast primaries (cancers)
  • Two or more individuals with breast cancer on the same side of the family (maternal or paternal)
  • One or more relative with ovarian cancer from the same side of the family (maternal or paternal)
  • First or second degree relative with breast cancer below the age of 45 years
  • Breast cancer diagnosed in a male relative
  • A women of Ashkenazi Jewish descent (high risk population for BRCA mutations and breast cancer)

Myriad Genetics holds the patent for BRCA testing and ever since Angelina’s news broke out, they have increased the prices of the test to $4000.