Following the decision for a preventative double mastectomy in 2013, Angelina Jolie announced this past March that she has had her ovaries and fallopian tubes removed in an effort to prevent cancer. A blood test showing a mutation in the BRCA1 gene gave her an 87 per cent risk of breast cancer and a 50 per cent risk of ovarian cancer.
Especially in cases for cancer, cardiovascular, and neurodegenerative diseases, precision or personalized medicine (PM) is a promising approach that identifies disease biomarkers for prevention and prediction of therapeutic measures and lifestyle changes. By using a blood, skin, or tissue sample to examine an individual’s DNA, clinicians are able to uncover defects or mutations that are known to be associated with a type of hereditary disease and can allow for early action and improved health outcomes (Canadian Cancer Society, 2015).
As a pioneer in PM, Canada is currently leading a large-scale national initiative with $67.5 million in research funding from the federal government through Genome Canada, Canadian Institutes of Health Research, and Cancer Stem Cell Consortium. The idea is to shift health care from a one-size fits all approach towards the adoption of evidence-based preventative care, which may ultimately improve health outcomes and health system costs.
Dr. Richard Kim is currently leading a transformative PM clinic at the London Health Sciences Centre in London, Ontario, which focuses on individualization of cancer drug therapy, vascular disease, and advanced drug reaction prevention among hospitalized patients. Since 2009, Dr. Kim and his team have worked closely with oncologists to treat breast cancer patients on tamoxifen chemotherapy to ensure the best clinical outcomes possible (London Health Sciences Centre, 2010). Research has shown that nearly one in ten Canadians have a genetic defect in a specific metabolizing enzyme that prevents tamoxifen from converting into its active form (Teft, Mansell, & Kim, 2011). When treated with tamoxifen chemotherapy, patients with this genetic defect are at a greater risk of breast cancer recurrence and even death.
Dr. Kim and his team have been referring patients for genotyping and blood level assessments to indicate the patient’s ability to metabolize tamoxifen. The use of PM allows the health care team to recognize the most effective drug treatments that work with, not against, a patient’s unique genetic code.
When Angelina Jolie announced her decision for preventative mastectomies, it not only heightened awareness but actually contributed to higher rates of BRCA genetic testing. Data from a genetic counseling service in Toronto, Ontario six months before and after Ms. Jolie’s announcement found a 90 per cent increase in referrals (487 women were referred for genetic counseling compared to 916 women after) (Sunnybrook Health Sciences Centre, 2014).
While many have praised Angelina’s brave message, there has also been criticism that the ‘Jolie Effect’ has led to unnecessary and dramatic treatments. Certainly there are advantages to genetic testing; however, critics warn of the physical, emotional, and long-term consequences of preventative surgery. Having increased CA-125 protein levels is not a strong enough reason for women to remove their ovaries. Awareness and access to genotyping technologies may have negative effects on the Canadian health system if not properly regulated.
Some companies have started marketing at home or direct-to-consumer genetic testing services. Without having to go to a clinic or speaking with a health professional, the consumer is notified of the results by mail or telephone. The idea is that with increased knowledge of your genetic information, you can make wiser health decisions based on your unique health risks. However rather than improving health outcomes, unregulated access to genetic information can potentially lead to greater frustration and unnecessary follow-up and use of clinician time and resources.
More knowledge is not always better and it is evident that this deeply embedded health care ideology needs reform. Diagnostic testing in Canada has increased rapidly in recent years and critics are beginning to question whether the potential benefits of these medical tests are outweighing the significantly large costs. We are at a pivotal point in the advancement of PM and the field of genomics; the challenge now is to meet increasing demands for genetic services, which includes screening, counselling, testing, and preventative surgery.
Considering the promising outcomes of PM, the implementation of evidence-based care needs to be carefully translated into clinical practice. Clinicians are not well-informed and very few have the skills to effectively provide and maximize benefits of PM. Canadian national research initiatives should allocate resources towards implementation research, which focuses on policies, guidelines, and pilot projects that enable health care innovation. With appropriate measures in place for wide-scale implementation, PM can prove to be a valuable opportunity for revolutionizing health care in Canada and around the world.
Canadian Cancer Society, 2015. Genetic testing. Retrieved from: http://www.cancer.ca/en/cancer-information/cancer-101/what-is-a-risk-factor/genetic-risk/genetic-testing/?region=on
London Health Sciences Centre, 2010. The DNA of Personalized Medicine. Retrieved from: http://www.lhsc.on.ca/About_Us/LHSC/Publications/2010/stories/story04/index.html
Sunnybrook Health Sciences Centre, 2014. ‘Angelina Effect’ on Breast Cancer Genetic Screening. Retrieved from: http://sunnybrook.ca/media/item.asp?i=1174
Teft, W.A., Mansell, S.E., & Kim, R.B., 2011. Endoxifen, the Active Metabolite of Tamoxifen, Is a Substrate of the Efflux Transporter P-Glycoprotein (Multidrug Resistance 1). Drug Metab Dispos, 39(3):558–562.
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