Wednesday, May 15, 2013

Angelina Jolie and Genetic Breast Cancer

I'm sure many of you heard about Angelina Jolie's editorial in the New York Times yesterday disclosing that she recently underwent prophylactic bilateral mastectomies due to her carrying the BRCA1 gene mutation.  I think what she did was an excellent medical decision and her choice to disclose this publicly, a brave one.  By doing so, hopefully more women will confront their own known high risk or find out more about their risk if they have a significant family history of breast and/or ovarian cancer. 

What exactly are BRCA gene mutations?  BRCA (which just stands for BReast CAncer) genes are two (BRCA 1 and BRCA 2) beneficial genes in our genetic code.  When functioning properly, they help to suppress tumors which may otherwise grow.  If you carry a genetic alteration in the BRCA 1 or 2 gene, then the suppression of tumors malfunctions, allowing cancers to develop.  BRCA genes primarily protect the breast and ovaries, so if you have one of these mutations, you are most susceptible to cancers in these two organs.  This is as high as an 80% chance of breast cancer and 50% chance of ovarian cancer. 

BRCA gene mutations are passed on generation by generation in a dominant fashion.  This means that any offspring of a carrier has a 50% chance of having the mutation, too.  Angelina's mother had the gene, as she died of ovarian cancer and any other siblings of hers would also have a 50% chance of having the mutation.  It's important to realize that the gene can be passed down from the father and that male offspring of carriers also have the risk of carrying the mutation.  Men who carry the mutation have up to a 6% chance of getting breast cancer (although this seems low, it is more than 6 times the 'average' risk for male breast cancer) and a 20% chance of developing prostate cancer.  And men and women carriers have additional risks of pancreatic cancer, melanoma and stomach cancers which are many times higher than those at general risk.  

As Angelina writes, knowing that you have the mutation empowers you to make proactive decisions about your health and medical care.  She chose bilateral mastectomies which is usually recommended prior to menopause (breast cancers in mutation carriers usually develop sooner than 'typical' breast cancers). And usually these women also undergo prophylactic removal of the ovaries and Fallopian tubes.  Until a woman is ready or prepared to make these decisions, however, mutation carriers are usually aggressively screened for breast cancer by annual screening mammography AND MRI from age 25 and ultrasound exams and blood tests to screen for ovarian cancer by age 30.  

It is important to remember that gene mutations only account for a small percentage (less than 10%) of breast cancers-so called 'genetic' breast cancers. Most breast cancers are 'sporatic,' meaning that there are no identifiable risk factors other than female sex and age.  Some breast cancers occur in multiple family members without the gene mutation.  These are called 'familial.'  It's likely that we'll eventually identify and be able to test for genetic alterations in these women.  

At my center, we screen all women for risk factors which may point towards a genetic mutation and/or an increased risk for breast cancer.  As a comprehensive screening and cancer treatment center, we have an on site genetic counselor to whom we refer patients at possible high risk.  If appropriate, we will test for the gene mutations (now just a 'swish and spit' test).  However, we strongly believe that all testing should be done in the presence of counseling in order to appropriately manage the results of the test, no matter what they are.

As we learn more and more about the biology of breast cancer and our own genetic makeup, I am optimistic that we will continue to identify more situations in which we can alter the natural course of genetic alterations.  It's exciting to work in a field which can offer hope and alternatives to patients who just a decade or so ago had to face cancer diagnoses at young ages which often led to devastating outcomes.  Knowing your genetic risks is an empowering and life-saving experience in many situations.  Angelina's disclosure of her own situation will raise awareness and save lives. 

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