Genetic Counseling 101

Most people are surprised when they hear that only 5 – 10% of breast cancer is hereditary. The other 90 – 95% of breast cancer is caused by environmental factors. Because I fall outside the ‘normal’ age range for developing breast cancer, my doctors want to see if I have a genetic mutation. Patients who have inherited breast cancer have a gene mutation in BRCA1 (Breast Cancer gene 1) or BRCA2 (Breast Cancer gene 2). I chose to go through with the testing which involves taking blood samples. From here, the test will take 6 months so I should find out the results sometime in October.

There can be a few different outcomes.

1. There is no gene mutation detected, chalk it up to some unknown environmental factor.
2. There is a gene mutation; the cancer was inherited; we do nothing.
3. Same as 2 except we make testing available to my parents to see who I inherited this from. This could lead to testing of other blood relatives if they chose to have the genetic testing done.

Just because someone has a BRCA1 or BRCA2 mutation does not mean they will develop cancer but their chances of getting cancer are increased. With BRCA1, breast cancer increases 50 – 85%, ovarian cancer increases 20 – 60% and prostate cancer increases 3 – 6 times. With BRCA2, breast cancer increases 50 – 85%, ovarian cancer increases 5 – 20% and prostate cancer increases 3 – 6 times.

There are many touchy issues with genetic testing. Some people just don’t want to know, which is completely understandable. Because I already know I have cancer, I want make information available to other family members (if they want it) that could possibly help them. For example, if I did have a gene mutation, other blood relatives would have access to testing for themselves, access to earlier preventative screening and access to earlier treatments.

The other sensitive issue surrounding genetic testing is genetic discrimination. Because insurance companies have access to your medical records, if you have a known gene mutation, you could possibly be denied insurance or be forced to pay huge premiums. I say ‘known’ gene mutation because everyone has some kind of gene mutation; either they don’t know it or scientists haven’t figured out the test yet.

On a funnier note, the genetic counselor went through a series of questions with me when we met. My favourite was, “How often do you have clinical breast exams?” I explained to her that she was the only medical person I had met in the last 3 months that didn’t want me to take my shirt off.

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