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Genetic Risk for Breast Cancer: The Whole Picture

by | May 22, 2013 | Integrative Cancer Treatments PMH

By Dr. Sharon Gurm BSc, ND, Naturopathic Physician, Clinic Founder & Clinical Director

Angelina’s Medical Choice

Earlier this week, Angelina Jolie announced her personal decision to have a radical double mastectomy after learning she is a carrier of a significant cancer gene.

Having an academic background in medical genetics and a clinical focus on integrative cancer care – and in particular, breast cancer – many have asked me to share my thoughts on Jolie’s decision. I welcome the opportunity to discuss this important topic of genetic factors and how they affect our risk for cancer.

Putting the spotlight on genetic risk

First off, I fully respect a woman’s right to make an informed decision. However, it’s unfortunate that Jolie and the involved media frenzy, didn’t embrace the powerful opportunity before them to fully inform women of all the facts about genetic risk and the impact of other factors, such those ‘epi-genetic’ factors scientifically established to influence the way these genes can affect the risk for developing breast cancer – or any cancer for that matter.

With the spotlight on this topic, it would have been great to educate women on some important considerations for genetic and inheritable risk for breast cancer. I suppose there’s still is an opportunity for those of us with an expertise and passion for the cause, to share some information and provide greater insight on the subject. If you find what you read is valuable, I hope you will pass it on. After all, knowledge is power.

No one-size-fits all approach

It cannot be overstated that a one-size-fits-all approach is far from the appropriate standard of care for a woman who learns she is a BRCA1 or BRCA2 gene carrier. It must be made clear that when a woman undergoes such radical surgeries, the risk for developing breast and ovarian cancer is diminished, but the gene defect still remains. Therefore, the risk of developing a cancer is still present and, according to the evidence available, can only be further reduced through certain chemo-preventive therapies, as well as dietary, nutritional and lifestyle factors that influence the way our genes behave.

If surgery is the chosen option, there are risks to be aware of. In addition to potential complications from surgery, if a woman chooses to have breast reconstruction surgery, the implants can make it more difficult to detect future cancers that may develop deep inside the chest wall.

Further, any major surgery has been shown to reduce lifespan and therefore, any decision for aggressive surgical intervention must be carefully weighed among the potential harms and benefit.

I’m sure Jolie didn’t make her decision lightly. I’m sure she weighed all the options. But that decision was for her. That is not to say all women who have a family history of breast or ovarian cancer, or those who learn they are a genetic carrier, should follow the same path as she has chosen for herself.

Every case is unique and even if a woman is a carrier of a cancer gene, there is a lot to be taken into consideration before making a decision on the appropriate course of action.

 The power of prevention

Here are some key facts to know about the BRCA1 and BRCA2 gene mutation and cancer risk:

  • Carriers of the BRCA1 or 2 genes can have anywhere from a 56-85% probability of developing breast cancer in their lifetime and anywhere from a 15-45% lifetime probability for developing ovarian cancer.
  • There are other genetic tests available that can help further stratify risk (determine the individual level of genetic risk among those who carry the gene), thereby assisting in the decision-making process.
  • A woman has the option to be screened more frequently, beginning as early as age 30, using a multi-modal approach (i.e. using more than just one type of screening technology) if she is a gene carrier. Given the number of recent advancements in breast imaging technologies (automated breast ultrasound, digital breast tomosynthesis, spectral mammography, MRI, digital mammography) not only can we detect breast cancers at an earlier stage, we can also better determine the degree of breast density (an important, independent and significant risk factor for breast cancer). In addition, women who carry the BRCA gene should be screened with semiannual transvaginal pelvic ultrasonography in addition to a blood test that measures levels of an ovarian cancer marker, known as CA-125. Early detection is associated with better outcomes.
  • For pre-menopausal women diagnosed with breast cancer the chemopreventive drug, Tamoxifen, has been associated with a 50-70% reduction in breast cancer in the opposite breast in BRCA1 and BRCA2 carriers (Gronwald et al., 2006). It may be effective in primary prevention as well, but this has yet to be proven.
  • Several studies have demonstrated the strong impact of diet, nutrition and lifestyle factors in women who are carriers of the BRCA1 and 2 cancer genes. These epi-genetic factors have tremendous influence on the way our genes behave. Here are just a few studies of note:
  • In 2009, a study featured in the journal Breast Cancer Research and Treatment demonstrated that women with the inherited mutation who ate more fruits and vegetables significantly reduced their risk of developing cancer compared to the women with the mutation who ate fewer fruits and vegetables.
  • A 2007 study featured in the journal Breast Cancer Research and Treatment found that women who carried the mutation and followed  dietary guidelines based on quality food choices and principles of macro-nutrient distribution, moderation, variety, and proportionality had a significantly reduced risk for breast cancer than the carrier group who did not follow the dietary guidelines. The researchers concluded a high- quality diet that meets specific guidelines, can constitute an effective preventive strategy for reducing BRCA-associated breast cancer risk.
  • In a 2006 study also featured in Breast Cancer Research and Treatment, women who carried the mutation and had normal weight and prevented weight gain as they aged also had much lower risk of developing cancer than women with the mutation who were overweight.
  • A 2012 study published in the journal Breast Cancer Research determined that breastfeeding for at least one year was associated with a 32% reduction in risk in BRCA1 mutation carriers, while breast-feeding for two or more years conferred an even greater reduction in risk.

In addition, carriers of the BRCA1 or BRCA2 gene tend to have higher levels of oxidative stress, which in turn leads to damage in DNA, thereby increasing the risk for cancer development.

Urinary levels of 8-oxo-dG (a marker for oxidative stress and DNA damage), which has been shown in studies to be higher in carriers of BRCA1 mutation, reflects the individual’s need for antioxidant supplementation (such as selenium, vitamin D and glutathione among many others) to counteract the DNA damaging effects of oxidative stress in the body.

A double-blinded placebo controlled study published in Cancer Epidemiology, Biomarkers and Prevention in 2009, found that the group of BRCA1 patients who were given antioxidant supplementation to reduce their levels of the urinary marker 8-oxo-dG had a lower incidence of cancer. I routinely run this test in my patients to understand their level of risk, their need for antioxidant and nutritional support, as well as to monitor the efficacy of treatment.

Before you decide, be informed

The take home message, is that there is a vast database of research supporting the efficacy and need for an appropriate preventative strategy to reduce a woman’s risk of developing breast and ovarian cancer if she carries the BRCA1 or 2 gene mutation, as well as other gene mutations.

What you have just read offers only a glimpse into the ocean of prevention and treatment research available for strategic planning and action. A personalized preventive strategy should be emphasized regardless of whether a woman chooses to undergo a radical double mastectomy and/or salpingoophorectomy (complete hysterectomy) or not. The point is if you are a carrier of the gene, you have a CHOICE. It is critical to have all the information before making a personal choice that is right for you.

I am a firm proponent of patient autonomy. I support my patient’s right to make a personal choice by ensuring they are well informed of all the evidence we have available, the possible options for management of their care and the harms and benefits of such options before they make a decision about their current and future health.

No matter what, be sure you know all the facts before making your decision and seek out the advice of 2 or 3 health practitioners, each with diverse medical backgrounds, with expertise in the care and management of breast cancer treatment and prevention.

Empower yourself

Knowing you have the gene is not a cancer sentence. Just like any challenge in life, if you learn you are carrier of the gene, take it as a call to action – an opportunity to expand your awareness and take control of your health. Ultimately, the decisions you make should EMPOWER you. If it does, then you’re on the right path.

Questions? Comments?

Join the conversation on Facebook and Twitter. Register to attend The Breast Event of The Tri-Cities, June 15th at the Inlet Theatre in Port Moody to learn more about what you can do to prevent breast cancer, engage with like-minded women, ask our speakers your questions and join the campaign to raise cancer prevention awareness!