There are limits to genetic testing

Genetic testing recommended to anyone with a suspicious family history

Angelina Jolie stunned the world when she announced that she’d had a double mastectomy and breast reconstruction surgery after finding out that she had a “faulty” gene linked to breast and ovarian cancer. For the first time ever, I became interested in a Hollywood boob job.

Jolie has put “a face” on hereditary causes of breast and/or ovarian cancer; and what a face it is. Some might say her face could launch a thousand ships, and now she has launched a few thousand headlines, catapulting breast cancer from the health pages to the front page.

Christina Applegate and Sharon Osbourne made similar announcements in the past five years, but received little fanfare, but thanks to Jolie, suddenly, everyone is aware of the existence of breast cancer gene mutations and preventative surgery.

There are however some misunderstandings that I’d like to clarify having spoken to a genetic counsellor.

First off, everyone has the BRCA1 and BRCA2 genes. However, if there is a mutation on either one, a person’s chances of breast and ovarian cancer go way up. According to Heather Dorman, a masters’ trained genetic counsellor, the risk in the general population for breast cancer is around eleven percent, but with a BRAC1 or BRAC2 mutation, that risk can jump into the fifty to eighty percent range.

Secondly, testing is not for everyone. Only five to ten percent of breast cancers are due to BRAC mutations. Looking for a genetic mutation in a healthy person with no family history is like looking for a needle in a haystack, says Dorman, and that’s why the province has set out criteria for testing to be covered by OHIP.

The criteria point to suspicious heredity. For example, if someone is under thirty-five and has been diagnosed with breast cancer, their doctor may refer them for genetic testing. Similarly, if two close relatives have had breast cancer under age 50, or if three or more women in a family have breast cancer, or if a man in the family has breast cancer, genetic heredity is more suspicious. If a woman has breast and ovarian cancer, testing is also recommended.

Dorman says that the next misconception is around who should be tested for the BRAC1 and BRAC2 gene mutation. Let’s say that I am healthy, but that my aunt and sister both have breast cancer. If I wanted to be tested for the genetic mutation, it would be very difficult to find (needle in the haystack). Instead, the blood would be drawn from my aunt or my sister, whomever was diagnosed with breast cancer at the earliest age. That way, there is a higher likelihood of finding a BRAC1 or BRAC2 mutation if it exists.

Dorman also likens the mutation to finding a “spelling mistake on the gene.” If a BRAC mutation is found in my aunt’s “book,” then I go in for testing and they know exactly where to look for the mutation, because families have the same spelling mistake. If I have inherited the gene mutation, it will be in the same chapter, page, paragraph, sentence, and word as my aunts.

(This also explains why the initial test for a family is $3-4,000 as the whole book has to be searched for a spelling mistake. In contrast, the follow up test costs around $100 because they simply turn to page 107 and check if that one specific word is spelled wrong or not.)

Testing is complicated by the fact that some relatives may not want to get the test done or may not be capable (as they may not have survived the cancer and blood tests can only be performed on the living).

A fourth misnomer is that preventative surgeries will eliminate the chance of developing cancer, but this is not the case. Post-surgery, the risk of breast and ovarian cancer, while vastly reduced, is not eliminated.

Dorman hopes that the recent media attention will reach those that have suspicious family history and that they will then start a conversation with their family doctor or health practitioner to get a referral for genetic testing.

Kudos to Angelina Jolie, Christina Applegate, and Sharon Osbourne for sharing their personal struggles and for being such empowering role models.

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