Genetic testing has been used throughout medical care. Young women have been offered and receiving genetic testing for many years. There are tests for your blood type, tests for those of Jewish heritage to determine if you are at risk for Tay Sachs or Canavan’s disease (the actual current panel we use tests for ten different diseases), there are tests to see if you are a sickle cell trait carrier, or carry the genetic material to pass on cystic fibrosis.
But generally the average 50 and older individual was never offered any genetic testing unless you actually have a cancer. Gradually this is changing. It is changing the way we will offer medical screening, it is changing how we treat diseases, and it is changing so rapidly that it’s moved beyond the physician’s office and into your kitchen. 23andMe stated on their Internet description in 2010 that they “provide(s) genetic testing for over 100 traits and diseases as well as DNA ancestry. Some of the test results you receive may be sort of fun: is your ear wax sticky or wet. Some may just be of interest: where did your genetic material mostly come from, mom or actually from dad? Others may be critically important: they can actually predict your likelihood of responding well to one type of blood thinner over another (should you need the blood thinner to begin with).
Knowing what company to use is as important as what test to get. The tests are changing rapidly. 23andMe tests for a very narrow range of some of the ways the gene can be abnormal, so you may be missed if your gene doesn’t get picked up by their test. Other companies test for so many gene abnormalities your health care provider may not be able to say what exactly the change means.
Genetic screening will not mean you can avoid medical screening tests like mammograms, that is a separate issue.
One test that has been in some use over the past 15 years has been for breast cancer and ovarian cancer susceptibility. Those that have breast cancer have been offered the BRCA1 and BRCA2 gene testing. You do need to know if your genes are normal or not, it has a huge effect on your life time risk of cancer! Those who carry these genes have a greater than 50% chance of recurrence of breast cancer, a greater chance of ovarian cancers, and there are risks of other cancers in their family. In 2013 it has come out that carriers are at risk for Fallopian tube cancers as well as cancers of the peritoneum (the tissue lining the abdomen). In fact about 60% of the cancers that are labeled serous tumors actually come from the Fallopian tubes rather than the ovaries. The average age of onset of ovarian cancer for a BRCA positive carrier is over the age of 55. Once someone tests positive they can inform family members who can then be screened and either will be negative: thus treated normally, or positive for the gene: and precautions can be taken. The screening tests are so poor that the newest advice is to take out both the Fallopian tubes and ovaries by age 35 or 40 rather than wait until you are older.
At Women’s Health Practice we also can offer panels of other genes that affect breast cancer risk, including a panel of 7 tests only two of which are for BRCA 1,2. There are also genetic tests on cancerous tissue that can tell your physician what will work for treatment if you do have breast cancer.
The bottom line is that genetic testing has just exploded onto the scene, and chances are your physician won’t even know all of what is available or more importantly how to interpret the results for you. Other questions like: who will own my gene test, who is over-seeing the accuracy of the lab methods, how will my insurance plan be affected do remain as well as wider ethical issues. You may want to schedule a WHP Telehealth visit to figure out if you need testing, or what the testing meant if you did a home test.