(March 6, 2009 - Insidermedicine) Dr. William Goodson, MD, discusses what one should do if one has a family history of breast cancer and wants to assess their risk for the disease. Dr. Goodson is a Senior Clinical Research Scientist at the California Pacific Medical Center Research Institute.
At the 2008 San Antonio Breast Cancer Symposium we spoke with Dr. William Goodson, Senior Clinical Research Scientist at the California Pacific Medical Center Research Institute.
If I had a family history of breast cancer...
Probably the central issue in terms of assessing risk is going to be your family history. You are going to start with a family history, and you will add to that your own personal history, in terms of parity (number of children), time of menstruation, time of menopause. You will go through general issues in terms of body mass, body weight; there are a whole variety of factors there.
One of the things that I think is very important in this regard is that if you are going to actually try to make that kind of assessment, you probably want to work with somebody who is a specifically trained genetic counselor. There are a lot of people who do this by the seat of the pants. And I think that is probably not a good way to do it; there is a lot of subtly to it. Its important when somebody starts talking about family history, to start with the issue of how many people are effected and how closely related they are to the person who is asking the question.
What tests might be performed?
About the only test that really gives us much useful information in this day and age is BRCA testing. There is BRCA1, there is BRCA2, and these are two specific genes that have been identified. Together even when they are positive they only count for a small percentage of breast cancer, less than 10%, more like 5%. When a person has one of these genes they have a very high risk of getting breast cancer. But obviously there are a lot of women who get breast cancer who don't have any kind of BRCA1 or BRCA2 mutation. There are mutations in what is called p53, there are mutations in p10. There is Li-Fraumeni syndrome, as well as some other syndromes that get tested for. The only really common testing however, is to test for BRCA1 and BRCA2 mutations.
What are the implications of a positive test?
If somebody tests positive, then the risk of breast cancer goes up quite strikingly. It is important to recognize that most of the numbers given, are in terms of risk assuming the patient lives to age 85. If somebody has a BRCA1 or BRCA2 mutation, and for simplicity I will address them together, their risk of breast cancer falls somewhere in the 65%-85% range by the time they hit age 85. That is the biggest risk.
For women probably the next biggest risk is ovarian carcinoma. Probably about 15% of women who have BRCA1 and BRCA2 mutations, there are slight differences, but basically we think about 1 in 6 or 1 in 7 women will get ovarian cancer. The real scary part about that is that ovarian cancer is much harder to detect. Breast cancer you can do mammography, you can do MRI, you can do all sorts of tests. For ovarian cancer you just happen to find it if you are lucky. There is also an increase risk of colon cancer and an increased risk of pancreatic cancer; those are probably the big ones. There is an across the board increased risk in a lot of cancers, but the main ones are breast, ovarian, pancreatic, and colon.
What are the drawbacks of labeling someone as "at risk"?
For a long time we were very concerned about issues of insurance, issues of employability. All of that changed in May of 2008 when they passed the legislation that basically makes it a federal crime in the United States to discriminate against somebody on the basis of BRCA1 or BRCA2 genetic inheritance; and in fact any genetic disease. You cannot discriminate against somebody. The possibility of being denied insurance or something like that strictly on that basis went away at that point. The other thing that comes up is the trauma or the anxiety that it induces in the patient. And I think this is particularly important in younger persons. Even if you have a BRCA1 or BRCA2 mutation the actual risk of getting breast cancer before age 30 is really very small, 1% maybe. There are so many issues in a person's life at that point that I think to dump worrying about getting breast cancer on somebody at that age is probably not fair.
We should also consider the risks that come in any kind of thing that somebody would choose to do to reduce their risk of cancer. And the biggest things that come up are choosing to do prophylactic mastectomy, or choosing to do oophorectomy and remove the ovaries. These are significant operations and carry with them risk of infections, all the risks of surgery, risk of bad results. All of those things are pretty uncommon, but they are not zero. A lot of what happens is that if somebody makes the decision that they are going to change their risk by doing something, the "doing something" to change risk, carries its own risk. That is where you really start to get into problems.
If I had a family history of breast cancer the first thing I would want to know is who in the family had breast cancer and how I was related to them. I would want to know whether or not that particular person had some kind of genetic mutation because if they didn't have it, there is no way that it is going to be detected in me. I would also want to know what options were available to do something about it. And particularly I would want to know the risks in terms of unexpected effects of taking steps to try to reduce risk. I would also want to know what the almost certain events, such as going through menopause, would have on my risk.