BRCA1 and BRCA2 genetic testing and opting for double mastectomies
Heard about Angelina Jolie getting double mastectomy done. Media and public are admiring her for making such brave decision. After reading some information on BRCA1 and BRCA2 gene here is my analysis. As per the data available so far the estimates of lifetime risk, about 12.0 percent of women (120 out of
1,000) in the general population will develop breast cancer sometime during
their lives compared with about 60 percent of women (600 out of 1,000) who have
inherited
a harmful mutation in BRCA1 or BRCA2.
It is important to note, however, that most research related to BRCA1
and BRCA2 has been done on large families with many individuals
affected by cancer. Estimates of breast and ovarian cancer risk associated with
BRCA1 and BRCA2 mutations have been calculated from studies of
these families. Because family members share a proportion of their genes and,
often, their environment, it is possible that the large number of cancer cases
seen in these families may be due in part to other genetic or environmental
factors. Therefore, risk estimates that are based on families with many affected
members may not accurately reflect the levels of risk for BRCA1 and
BRCA2 mutation carriers in the general population. In addition, no data
are available from long-term studies of the general population comparing cancer
risk in women who have harmful BRCA1 or BRCA2 mutations with
women who do not have such mutations. Therefore, the percentages given above are
estimates that may change as more data become available.
The likelihood of a harmful mutation in BRCA1 or BRCA2 is
increased with certain familial patterns of cancer. These patterns include the
following:
- For women who are not of Ashkenazi Jewish descent:
- two first-degree relatives (mother, daughter, or sister) diagnosed with breast cancer, one of whom was diagnosed at age 50 or younger;
- three or more first-degree or second-degree (grandmother or aunt) relatives diagnosed with breast cancer regardless of their age at diagnosis;
- a combination of first- and second-degree relatives diagnosed with breast cancer and ovarian cancer (one cancer type per person);
- a first-degree relative with cancer diagnosed in both breasts (bilateral breast cancer);
- a combination of two or more first- or second-degree relatives diagnosed with ovarian cancer regardless of age at diagnosis;
- a first- or second-degree relative diagnosed with both breast and ovarian cancer regardless of age at diagnosis; and
- breast cancer diagnosed in a male relative.
- For women of Ashkenazi Jewish descent:
- any first-degree relative diagnosed with breast or ovarian cancer; and
- two second-degree relatives on the same side of the family diagnosed with breast or ovarian cancer.
My impression: Angelina Jolie decided to get double mastectomy done as a preventative measure. She is of a Jewish descend, and had mother who died of breast cancer at age of 56. That sure makes her fall in a high risk category, however not enough research is done regarding accurate percent estimate of people with that mutation who go and develop the cancer. Also there are side effects of mastectomy, Being a PT, I have seen several patients who struggle with post surgical lymphedema. I think following preventive care of MRI every 6 months for females found with mutated gene is a wiser choice than getting a preventive mastectomy done.
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