Dr. John Link Interview
February 22, 2013 at 2:59 PM
Greg Dennis: Welcome to the Symphony Sisterhood Breast Cancer Dialogues. I’m Gregory Dennis. We’re talking today with Dr. John Link who is a noted medical oncologist and also one of the world’s leading breast cancer specialists. Dr. Link is author of the Breast Cancer Survival Manual and he’s also a founder of the Breastlink Medical Group. Dr. Link, despite the recent advances in the science and medical treatment, many women who are newly diagnosed with breast cancer still feel that they absolutely ought to have chemotherapy whether or not it’s appropriate. Is it still true that every woman who is diagnosed with breast cancer should get chemotherapy, and if not, why not?
Dr. John Link: Yes, that’s a good question. I think that you know our knowledge of breast cancer has increased tremendously in the last few years, over the last few months actually. It’s really, it’s really exponentially changing. But the truth is that a majority of women with newly diagnosed breast cancer do not need chemotherapy. Breast cancer is a very heterogeneous disease and certain subtypes that we now can identify genomically need chemotherapy very frequently, the majority of breast cancer falls into what we call the hormone-positive type of breast cancer where there are hormone receptors on the surface of the breast cancer cell. We call those luminal type breast cancers and five years ago, seven years ago, any cancer in that group that was over 10 millimeters, women were at least recommended to consider chemotherapy. That’s changed dramatically now and a majority of those women do not need chemotherapy based on new testing techniques. So the truth of the matter is cytotoxic kinds of chemotherapy treatments are cell poisons and work pretty indiscriminately to poison rapidly dividing cells. Many breast cancers are not rapidly dividing and we do much better with targeted hormonal type therapy. So, long answer but the short, short kind of synopsis is I would say today, 30% of women will be offered chemotherapy. The rest will have such early cancer they don’t need it, or they don’t have the type of cancer where it particularly works well.
Greg Dennis: And if chemotherapy is offered or recommended, is there a value in getting a second opinion?
Dr. John Link: I think so because of what I just discussed this kind of rapid change that’s occurring. Unfortunately, many of my colleagues and particularly ones that deal with all types of cancer, what we call general oncologists, are practicing the way they practiced a year or two ago and things have changed. So with new testing and new knowledge we now can, many women that we used to recommend chemotherapy for, we don’t anymore. So I think if a woman wants to be on really solid ground, she probably should get a second opinion from a facility that specializes in breast cancer that has a collaborative program where doctors coordinate care and where there is a tendency to really be very current in the most up to date knowledge.
Greg Dennis: Now speaking of up to date knowledge, in your book The Breast Cancer Survival Manual, you speak about a genomic revolution in breast cancer. What do you mean by that?
Dr. John Link: Well, we now have the tools to actually explore the DNA of the breast cancer cell and what we have to remember is that the breast cancer cell comes from – the origin is in normal breast duct cell or a breast cell. So it is a woman’s cell that’s gone awry and we now have the ability to look into the DNA to the mutations and into the changes that have occurred in that one cell that had led to it to become what we call cancerous. The old way we used to diagnose cancer was through a microscope and we would look for certain characteristics. We still do that but now we have this deeper level of looking at a cancer cell with, you know, looking at it genomically at the actually genes. The genes not only tell us what kind of cancer it is, but it also they tell us what pathways have been distorted, and this has the potential to tell us what targeted therapies that we can use. So that’s the genomic revolution and it is upon us, and it really is going to change, it already has changed the way we manage cancer.
Greg Dennis: Well, before we talk a little more about how it’s changing the management of cancer, I want to ask you, I’m sure a lot of people have heard about genetic tests for breast cancer. But you were speaking about genomic testing. Briefly, what’s the difference?
Dr. John Link: The difference is genetic testing is a blood test or sometimes we use saliva or a mucous membrane, take a little scraping from the mouth and look at a person’s cells, and we look at it to see if a woman carries a certain inherited abnormality or difference that makes her more susceptible to a particular type of cancer. In breast cancer that would be BRCA1 and BRCA2 testing. Those are the most frequently done. So it shows a predisposition to getting cancer where this hereditary cancer goes through a family from father to daughter or mother to daughter. Whereas genomic testing which we just referred to is really the analysis of the actual cancer cell itself looking at those genetic changes.
Greg Dennis: I see. Well, so let’s talk about some of those genomic tests. I understand you sometimes use the MammaPrint test. How do you use that and what do you perceive its value to be?
Dr. John Link: The MammaPrint test is a gene signature test looking at I believe it’s 70 genes that have been shown to be associated with breast cancer malignancy with certain – and by analyzing these genes we can assess risk of the cancer spreading into the blood stream. So, and this risk has been validated both retrospectively from a large bank of tumors breast cancer that had been stored and we know the outcome of those women, and it’s been validated prospectively doing the test and then following the women for five or six years. What we know is that this analysis of the genes predicts who is going to do well and who is not. And so the MammaPrint test is a 70-gene signature that can tell us that a woman has a less than 10% chance of relapsing in her system, in her body, in a 10-year period. And most of those women then do not need chemotherapy because their risk is low. On the other hand, it also identifies women that are at high risk or higher risk where chemotherapy and systemic therapy may be a benefit.
Greg Dennis: I see, and what about the blueprint genomic test? What is that and how does that fit with what you call the genomic revolution?
Dr. John Link: Yes, so that’s another of these gene signatures. It’s I believe an 80-gene signature that actually categorizes the cancer into one of three or four major types of breast cancer that allows the treating doctor to pick the right targets and the right therapies. So there are basically four types of breast cancers genomically described, and then there are going to be many subtypes of those, but the four types are the luminal hormone positive type and there’s a luminal A and a luminal B. A MammaPrint actually helps us decide between A and B. Then there is what we call the basal B-A-S-A-L type or the triple negative type. Triple negative means it’s the receptors on the cancer cell are negative for the three receptors, the ATR2, the estrogen and the progesterone receptors. So that’s called triple negative or basal. And then the fourth type is called the ATR2, the HER2 type of breast cancer where an alcogene has been amplified or over-produced by the aberrant or abnormal gene, and that gene which has gone out of control, has gone berserk, is making a protein that turns the cells on and accelerates the cancer. And there’s a receptor that indicates that that protein has been turned on.
Greg Dennis: I see. So we’ve been talking about how genomic tests would help identify women at low risk or high risk of recurrence and how genomic testing can help guide treatment choices. In addition to chemotherapy, there are other types of treatment such as radiation or hormone therapy that women might be offered. How does that tie in with genomic testing?
Dr. John Link: Radiation is an addition, an adjunct to surgery. So it’s pretty much a local control issue. So any women that have lumpectomies rather than mastectomies will have radiation added to prevent what we call local recurrence. So generally radiation should be thought of in the same vein as surgery. Hormonal therapy is a systemic therapy that is usually an oral drug, a pill which is used to affect the luminal type of breast cancer that has hormone receptors, and those hormone receptors on the surface of the cancer cell are targets for these hormone treatments that we prescribe. The two classes, one are called aromatase inhibitors, the other are called SERMs or selective estrogen receptor modulators, and Tamoxifen is the common one of those.
Greg Dennis: I see. So before we wrap up today, Doctor, are there any other thoughts that you want to offer about genomic testing and diagnosis and treatment of breast cancer, any take-away messages for women who are newly diagnosed?
Dr. John Link: Well, as I said, I think it’s a very exciting time and things are rapidly changing. So I think to just reemphasize that I think before embarking upon chemotherapy, that a woman might want to seek a second opinion to make sure that she does indeed need chemotherapy based on genomic testing. Secondly, the types of chemotherapy that we use for the particular types of breast cancer are changing and have been elucidated by retrospective studies looking at genomic testing. So drugs such as Adriamycin which we used to use very frequently in most types of breast cancer are now being pretty much reserved for HER2-positive, the HER2-positive type of breast cancer. So I strongly believe a woman is serving herself best by getting a second opinion if there’s any question. And you know the issue, she doesn’t need to be afraid that she’s going to offend her doctor. It’s very commonplace now to seek second opinions.
Greg Dennis: Well, thank you very much for your time, Doctor. It’s been a pleasure talking with you about genomic testing and all these other issues. And again, Dr. Link is a respected medical oncologist, founder of the Breastlink Medical Group, and author of The Breast Cancer Survival Manual. Thank you, Doctor.
Dr. John Link: Thank you.
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