Episode Transcript
Interviewer: Should every woman over 30 receive genetic testing for breast cancer? Up next on The Scope. Examining the latest research and telling you about the latest breakthroughs. The Science and Research Show is on The Scope.
I'm talking with Wendy Kohlmann, a genetic counselor at the Huntsman Cancer Institute at the 人妻中出视频 of Utah. Ms. Kohlmann, explain the viewpoint that was published this month in the Journal of the American Medical Association.
Wendy: Dr. Mary-Claire King gave a very thought provoking presentation and article regarding the idea of population based screening of the BRCA1 and the BRCA2 genes. Typically we have relied on the tool of family history to help us identify families that maybe have mutations in these high risk genes.
We looked for families that have features such as multiple women with breast or ovarian cancer, women who develop breast cancer at younger than average ages, women who develop both breast and ovarian cancer or perhaps bilateral breast cancer. Those were all red flags that maybe there was a mutation in one of these genes being passed through the family.
Dr. King suggested kind of a new approach to this. Rather than relying on family history as the tool for identifying families that may be at risk she suggested that it may be beneficial to think about just testing all women for this mutation.
Interviewer: Why focus on the BRCA genes?
Wendy: Mutations in those genes are quite rare; however, when a mutation does occur the risks in these families is greatly increased. The risk for breast cancer can go up to 50 to 80% and the risk for ovarian cancer can be elevated as high as 60%.
Also there are very well established screening and prevention recommendations for women with mutations in these genes. We can screen for breast cancer at an earlier age or more carefully using things like mammograms and breast MRI's, some women also opt for prophylactic surgery to remove the breast or ovaries before cancer develops, so Dr. King's argument was that even though these mutations are uncommon, you know, if they are present in a family the risks are very high and there are very specific things that the women in those families could do to reduce their risk if they were alerted in advance.
Interviewer: So why does she think that knowing the family history may not be good enough?
Wendy: Some families are just very small and there are few relatives and it's hard to see a strong pattern. Also, for mutations in genes such as BRCA1 and 2 that tend to cause an increased risk for cancers, most specifically in women, if you have a family that just happens to have lots of male relatives as opposed to females, this mutation could be passed through generations of men who don't develop the cancer and we won't see that until it shows up in finally a female granddaughter for instance.
Interviewer: But I thought mutations in BRCA could cause breast cancer even in men.
Wendy: They can, the risk for a man with the BRCA mutation to develop breast cancer is only about 6%.
Interviewer: And do we have a sense of how many women do not get tested for BRCA that actually carry the gene?
Wendy: We are probably missing a fair number. We recently completed a study at Huntsman that was looking statewide at women who meet the current guidelines for genetic testing which are based on family history and we contacted women throughout the state and found that of women who meet current genetic testing guidelines, only about 20 to 30% of them had previously been tested so certainly, there are barriers to this getting done.
Some of it is information, some of these women reported that their doctor had never brought it up to them, they weren't aware that this testing was available. Other barriers are cost and insurance coverage which can still be a problem.
Interviewer: So her recommendation is in addition to you know, your typical mammogram, she's recommending that women over 30 undergo testing for the BRCA gene. What do you think about that recommendation?
Wendy: At this point in time there are lots of steps or pieces that would need to be put in place before we could really begin something like that very effectively. Dr. King, kind of based her recommendation on a recent study that she did in Israel and individuals of Jewish ancestry, there are three common mutations in the BRCA1 and 2 genes that account for the majority of hereditary breast/ovarian cancer in that population.
So in that population the likelihood of having a mutation is much higher than in individuals who don't have Jewish ancestry and also the testing is much simpler because we only have to look for three mutations as opposed to looking for the thousands of mutations that have been identified in individuals of non-Jewish ancestry so it's a little hard to take that study and say, okay now we can do this for everybody in any country.
Interviewer: With the thousands of mutations in BRCA that have been found are all of them high risk factors for developing breast cancer?
Wendy: So not all variations identified in a gene will necessarily be associated with disease risk and this is really one of the big challenges that we need to address before we could implement population based genetic testing of these genes. Sometimes changes will be identified in the gene and it's not clear whether or not that is, you know, that change in the genetic code would actually damage the protein being produced by that gene or if it's just part of kind of what makes everybody unique.
Interviewer: Right and I guess some of it is psychological. I mean, if you know that you have variations it may cause anxiety even though we don't know if there's really a basis to be worried about those results.
Wendy: You know, that can certainly be part of it. Studies have shown this that women who are found to have these variants of uncertain significance, in some cases have almost as much as anxiety as women who are found to have mutations because they've been told, well, we've found something but we don't know what it means and so there can be anxiety that goes along with uncertain findings.
Interviewer: You would say that at this point we're not quite ready for population based testing because we don't know how to interpret all the information that may come back. Are there any other factors we should take into consideration?
Wendy: Lots of logistical issues would probably need to be addressed before we could, in a really cost effective way, do the whole population. Right now there's a hodge podge of commercial laboratories throughout the country offering BRCA testing. Each one may be using slightly different technology, each one may be interpreting some of these genetic variants a little bit differently.
We also don't have consistent and uniform ways of tracking genetic testing in a lot of electronic medical records so if a women has one doctor at age 30 who orders this test but then switches to another healthcare provider, how is that information going to follow her through the healthcare system, but like I said, and I think that, you know, having discussions like the one Dr. King has initiated is really going to help us start breaking down these problems and figuring out how to solve them.
Interviewer: And so what would your recommendation be at this point?
Wendy: So for women who have a family history of breast cancer, we do encourage them to talk to their doctors or contact Huntsman Cancer Institute for more information. Like I said, even among women who have a family history of breast cancer that is not necessarily indicative of BRCA1 and 2.
For women who don't have a family history of breast cancer, at this point in time, these tests are typically thousands of dollars and the likelihood of there being a mutation is very low so we would encourage them continue to work with their doctors, follow general population screening recommendations. In the future as our genetic testing technology evolves wider spread testing may become an option or even the recommendation.
Interviewer: Interesting, information and all in the name of better health. This is The Scope 人妻中出视频 Sciences Radio.