Welcome to Mayo Clinic podcast. Our topic today is prophylactic mastectomy and other cancer-preventive procedures — what you need to know. I'm your host, Rich Dietman.

In today's podcast we're talking about what to consider when deciding on whether prophylactic mastectomy is right for you. My guest is Mayo Clinic cancer specialist, Dr. Tim Moynihan. Dr. Moynihan practices in the department of medical oncology at Mayo, and he's also a cancer medical editor for MayoClinic.com. Dr. Moynihan, thanks for being with us.

Dr. Moynihan: Thank you for having me here, Rich.

Rich Dietman: First of all, just exactly what is prophylactic mastectomy?

Dr. Moynihan: Prophylactic mastectomy means removing the breast when there's no disease evident in it, in an attempt to prevent a future problem with the breast.

Rich Dietman: And who are candidates for this procedure?

Dr. Moynihan: Most women should not think about doing prophylactic mastectomy. Only women who are at very, very high risk for developing breast cancer would be appropriate candidates for prophylactic mastectomy. And this may include women who have a very strong family history of breast cancer or who have an inherited abnormal gene that increases a risk for breast cancer, such as those people who have the BRCA1 or 2 mutations within their family, because those people do have a very high lifetime risk of developing breast cancer. There are other women who are at high risk for breast cancer, including for example, women who have had radiation to the upper part of their chest, especially during the early teen years, during the ages when breasts normally develop. Those women, 10 years after having completed their radiation, are at very high risk for developing cancers within the parts of the breast that were exposed to the radiation. So they should consider removing the breast before they're giving them a problem. There are a few other hereditary conditions that may predispose to this also to be considered, but this represents a vast minority of cancer patients.

Rich Dietman: So it's not a large, large number of women who have to consider this or think about it.

Dr. Moynihan: No, I should also mention, perhaps, women who have breast cancer in the other breast. It's something for them to consider. Again, the vast majority should not do that because the vast majority of women with cancer in one breast will not likely get it in the other breast. There are some subsets, though, that may be more likely. For example, those women who have lobular carcinoma in situ in one breast — much higher risk of having cancer in the other breast sometime in the future. So those women might at least want to consider that. They should discuss this very carefully with their oncologist before making that decision.

Rich Dietman: What choices does a woman have who is at risk, and it's been determined that she's at risk, other than prophylactic mastectomy?

Dr. Moynihan: Prophylactic mastectomy is one technique that we have that is a big operation. It's a fairly radical thing to do because it does change your body and all. But it has been shown to decrease the chance of breast cancer substantially in the breast. We do have other choices. One would be there are some medications now that have been shown to decrease the chance of developing breast cancer. The most commonly used one is a medicine called tamoxifen. There's a medicine that's similar to that called raloxifene, and both of these do decrease the subsequent chance of developing cancer. Now these medicines do have potential side effects, so you need to pay attention to those and try to weigh the benefits of it versus the risks.

Rich Dietman: Talk about some of the other prophylactic procedures that are available to people who may be at risk for cancers other than breast cancer.

Dr. Moynihan: There are things that we do consider in those people who have a strong family history of, let's say, colon cancer. There are hereditary forms of colon cancer. Again the minority of colon cancers are hereditary, but some are. For example, in people who inherit a gene called familial adenomatous polyposis gene, most people who have that gene by the time they're 40 will develop colon cancer. If we know that gene's in your family, we would consider removing your entire colon prior to age 40. People with ulcerative colitis are also at a higher risk for developing colon cancer. Especially if the ulcerative colitis has had a lot of flares or a lot of problems with flare-ups of that disease. In that setting it may be worth removing the colon before it has a problem. Those would be the two major prophylactic operations that we do, either for the breast or the colon. For specific other individuals, there may be other procedures to consider, but this would be on an individual basis.

Rich Dietman: These procedures are pretty drastic — at least they seem that way, I'm sure, to someone considering them. How does a person prepare for such a procedure in terms of adjusting to it, coming to terms with that?

Dr. Moynihan: All right, these procedures would never be taken lightly. So it has to undergo very careful consideration as to what the procedure means to somebody and what is their chance of developing a problem if we don't do their procedure. Furthermore, how much can we reduce the chance of a future problem by doing the procedure? None of these procedures are 100 percent foolproof. There are people who undergo prophylactic treatment for something and still the cancer may still show up. For example, in breast cancer we know that prophylactic mastectomy reduces the chance of getting cancer by up to 95 percent. That means there's still a small percentage of people who still have it, even in spite of that. Ninety-five percent risk reduction is pretty good, but it's probably as good as we can possibly get in medicine, since nothing's 100 percent. So these can be disfiguring operations, significant recoveries from these operations, and significant other complications can happen with it. So we have to make sure that the benefits of the treatment outweigh the risks of the procedure itself.

Rich Dietman: And speaking of determining the level of risk, when it comes to breast cancer and it comes to a person's genetic inclination to breast cancer, how reliable, how accurate is genetic testing these days when it comes to assessing that risk?

Dr. Moynihan: It's variable, and it's really dependent on the individual's family history. If there's a family history where there's an extensive number of cases of breast cancer, particularly at a young age, or several women with bilateral breast cancer, or several women with either breast and/or ovarian cancer, those families have a high likelihood of having a gene abnormality. We know of several of the gene types to test for, but we don't know all of them. So one thing we always do is make sure that if we do test somebody in the family, we always try to test somebody who actually has the cancer first. If we can find a gene abnormality in the person who has the cancer, then we know what gene abnormality to look for in those people who don't have cancer or are considering these prophylactic operations. If we can find the gene abnormality in somebody who has the cancer, then a relative of theirs may have a 50-50 chance of inheriting that gene only. So we don't want to just automatically do it on the family history because half those people wouldn't need that. So if we can find it in the person with the cancer, and we also find it in the person who's related to that individual, they have it, then that may tell us that their lifetime risk of cancer is fairly high. And we can substantially reduce that with the prophylactic operation. If we go and test somebody who's not affected by the cancer, just because of a strong family history, we have a much higher likelihood of missing something because we don't know quite what to look for yet. So these tests are not 100 percent reliable. They are better than they used to be. We're learning more things to look for. But there are still many, many different hereditary abnormalities out there that we still just don't know exactly what to look for.

Rich Dietman: In the case of a woman considering prophylactic mastectomy, besides talking with her doctor, who else should she consider talking to in making this decision?

Dr. Moynihan: We strongly recommend talking to a genetic counselor, because these can be hereditary conditions and there's many implications of those — both the testing itself which, although the testing for the individual is fairly easy, it's just a blood test, typically, that we do, the cost of the test and what you're going to do with that information are very important. So those are the bigger constituents to a genetic counseling event prior to doing the test. In addition, the genetic counselor can screen the whole family, develop a very large family tree, and then by the use of that may be able to predict what's the likelihood of one of our tests finding something. So it may help guide us as to whether or not we should do the test. One of the problems with the test is that often insurance companies will not pay for the test itself. So oftentimes this is an out-of pocket-expense for the individual. And if it's one of the standard mutations we're looking for, and we find it, that expense may not be too great, in the number of several hundred dollars. If we're looking for something new or something different, it can get into the several thousand dollar range and be much more expensive. Another thing that a lot of people are concerned about when we ask them to see genetic counselors is many people are concerned about future insurance concerns for themselves or other family members who test positive for this gene. Although there are laws in place that may protect against insurance discrimination, there still is concern about that. Fortunately, we have not seen a lot of that happen, and most states do have laws that prevent insurance companies from discriminating on hereditary conditions.

Rich Dietman: Thanks very much, Dr. Moynihan. We've been talking about what to consider when deciding on prophylactic mastectomy or other cancer-preventive procedures with Dr. Tim Moynihan, a cancer specialist at Mayo Clinic and cancer medical editor for MayoClinic.com. You've been listening to Mayo Clinic podcast. I'm Rich Dietman.

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