Getting the Facts on Genetic Testing

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Angelina Jolie’s recent editorial in the New York Times resulted in a whirlwind of discussion.  Her announcement to decide to undergo a double mastectomy was based on genetic testing that revealed she carried a “faulty” BRCA1 gene that significantly increases her chances of developing breast and ovarian cancer. Jolie had witnessed the devastating effects of cancer and lost her own mother to the disease several years ago. The mother of six admitted that the decision was difficult to make but foremost in her mind was living a long and healthy life and being there for her children.

Prophylactic mastectomy, or surgical removal of the breasts and/or oophorectomy, removal of the ovaries as a preventative measure is not a new procedure, but Jolie has brought a great deal of attention to it due to her celebrity status. No doubt this was her intention – to raise awareness about genetic testing and the options available. But what are the facts around this testing and who should be tested?

BRCA1 stands for breast cancer susceptibility gene 1. Both BRCA1 and BRCA2 are genes known as tumour suppressors, which normally prevent cancer from developing. Women found to have mutations in the genes have a very high risk of developing breast and ovarian cancers.  Only one in 500 to one in 1,000 individuals will carry a mutation or a gene change in one or another of these genes so the risk factor, while serious, is not common.

According to the Cancer Society, the chance of breast and ovarian cancers being linked to the mutated genes are highest among the following families:

  • Those with a family history of breast or ovarian cancer;
  • Early onset of breast cancer in one or more female relatives before age 50;
  •  Breast and ovarian cancer in a single relative;
  •  Family members developing cancer in both breasts;
  • A male relative with breast cancer.

A family history of breast cancer, while a serious risk factor, is not necessarily an indicator of a known genetic link. No doubt further research and investigation will reveal other “faulty” genes in the future.

A genetic test for cancer predisposition is a blood test that shows whether an individual has inherited a gene mutation that increases the risk for certain cancers. Individuals with a personal or family history of breast, ovarian or colon cancer may see a genetic counsellor to discuss cancer risks and clarify eligibility for genetic testing. Genetic counselling and testing is paid for by the Ontario Health Insurance Plan (OHIP). There are certain criteria an individual must meet to be eligible for genetic testing, including a strong family history of cancer, young ages of onset of cancer within the family and being a member of ethnic groups known to be affected.

If you are worried that you might be at risk, your first step is to discuss your concerns with your family doctor.  If necessary, they will refer you to a familial cancer clinic, part of the Predictive Cancer Genetics Program funded by the Ministry of Health and Long-Term Care. A full list of these sites is available on the Cancer Care Ontario website: https://www.cancercare.on.ca/

Not every woman may choose to follow in Jolie’s footsteps. Making a decision to have any healthy body part removed is a radical move and every surgery has some accompanying risks and side-effects. Emotional and psychological effects of surgery are also an important factor and well worth considering.

Some radical opinions even suggest that genetic testing is just a form of “medical hexing” and that if you believe that you are predestined to become ill you will.

On the positive side, regular breast screening can be beneficial to all women, regardless of their risk factors. The Ontario government recently announced that it has decided to replace nearly a quarter of the mammography machines in the province because a new study has revealed that they are 20 per cent less effective in detecting breast cancers than other devices.  Ontario women will be able to take advantage of the higher accuracy rate of digital technology or direct radiography machines which will replace the CR devices which are also being used in the province.

Also helpful are lifestyle factors such as limiting consumption of alcohol, eating a low-fat diet and engaging in regular exercise. Getting informed about breast cancer is an important step towards prevention and hats off to Jolie for having the courage and conviction to bring attention to this sensitive subject.

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