Current Research in Breast Cancer
ARLINE KALLICK: Welcome to the Y-ME Sharing Network Teleconference. Our call will begin tonight with tonight’s speaker, Dr. Larissa Korde. Dr. Korde is a clinical researcher in the clinical genetics branch, the division of cancer epidemiology and genetics at the National Cancer Institute. Her research interests include lifestyle factors and their effect on breast cancer risk, and the identification of intermediate endpoints for cancer prevention and treatment trials, and designing intervention trials for populations of increased risk. She is also a member of the gynecologic oncology group, and is involved in a number of studies that relate to women at an increased risk for breast and ovarian cancer based on a genetic or familial predisposition.
The presentation will be followed by a question and answer session, and then end with small group discussions. Our topic is “Current Research in Breast Cancer.” We realize that it’s difficult to answer everyone’s question in a one-hour teleconference. If your question does not get presented during the question and answer portion or the group discussion, please contact the Y-ME hotline at (800) 221-2141. The hotline is answered by certified peer counselors who are breast cancer survivors, and it is available 24/7. When presenting a question to Dr. Korde, please be courteous to other callers by keeping your question brief, and realizing that this cannot be a private consultation. A transcript of each call will be available at our website one week following the call. Just visit our website at www.y-me.org.
We are now ready to begin with tonight’s teleconference. Welcome Dr. Korde.
DR. LARISSA KORDE: Thanks so much, and thanks to everybody for calling in this evening. I’d really like to thank Arline and Y-ME for giving me the opportunity to speak to you, and to provide an update on breast cancer research. I’m going to focus specifically on research presented at this year’s San Antonio Breast Cancer Symposium. To begin with, let me just say that while I don’t think any of the data presented at this year’s meeting will result in drastic changes in practice of patient management, I do think that there is a lot of interesting findings, and I’ll try to highlight some of those this evening. In terms of broad areas, I think a couple of messages that I took home from this year’s meeting were, first, that we’re really moving toward being able to treat breast cancer in a more individualized manner; taking information that we know about on a particular patient and about her tumor to choose the best and least toxic therapy. And two, that as our therapies continue to improve and we have more and more cancer survivors it’s really important to focus on understanding and minimizing toxicities and side effects associated with the therapies we’re using.
I’m going to cover four specific topics. First I’ll discuss studies aimed at better tailoring therapy for individual patients. Second I’ll talk a little bit about some data relating to the uses of specific chemotherapy type that we use quite frequently in the treatment of breast cancer, and that’s a class of drug called anthracyclines. Third I’ll present an update on hormonal therapies, specifically in the adjuvant setting. And then lastly I’ll discuss some data related to bone health in women on adjuvant hormonal therapy. I know this is obviously a healthy slate, a lot to cover, and I’m just going to speak pretty generally about each of these topics for about five minutes and then we’ll open up to questions.
The first topic I’d like to discuss is a growing number of studies addressing the idea of being able to better tailor therapy for individual patients. By that I mean more accurately predicting, first of all, which patients are more like to have a recurrence of their disease, and therefore need the most aggressive therapy. And then secondly, which patients are most likely to benefit from either a particular general type of treatment such as hormonal therapy or chemo, or specifically from a particular agent or drug. And there were a number of studies at San Antonio that addressed this broad issue of so-called tailored therapy. The first I’d like to highlight is a study presented by Dr. Kathy Albain on behalf of a group of investigators from one of the large clinical trial groups in breast cancer called the Southwest Oncology Group. That trial looked at the ability of a test called Oncotype DX to predict which patients with hormone receptor positive lymph node-positive disease would benefit most from the addition of chemotherapy to hormone therapy.
So just to back up a little bit let me talk about the Oncotype DX test. It’s a test that’s done on tumor tissue, and it looks at the expression of a panel of 21 genes. It’s previously been studied in the setting of hormone receptor positive lymph node-negative breast cancer. The test gives a numeric score, and previous studies have shown that women with a high recurrence score are at the greatest risk of having their cancer return, while women with a lower recurrence score are at a lower risk of recurrence. In addition, and perhaps more importantly, women with high recurrence scores benefit from chemotherapy in previous studies, while those with a low recurrence score had equivalent outcomes whether they received hormonal therapy alone or the combination of chemo and hormones. This suggests that this group of women, those with a low recurrence score, could potentially avoid chemotherapy and its toxicities.
The study presented this year by Dr. Albain was done in post-menopausal women with hormone receptor positive lymph node-positive breast cancer. That’s different from what I described before because the patients in this trial had disease in their lymph nodes at the time of diagnosis, which we know is associated with a higher risk of recurrence than having disease that doesn’t involve the nodes. However, the study’s findings were remarkably similar to what was previously seen in node-negative patients. And that is, so let me just give you a little overview of the actual trial. All the patients in the study received hormonal therapy, specifically Tamoxophin therapy. And patients were then randomized to receive either six cycles of anthracycline-based chemotherapy or no chemotherapy. And then the Oncotype test was done on all the patients. And they looked back to see which patients benefited, what their recurrence score was, and how those things correlated. So the main finding was that women with a high recurrence score seemed to derive a large benefit from chemotherapy. So those who received chemo did better than those who didn’t. And those with a low recurrence score did not seem to benefit from the chemo. So the outcomes were equal in patients who got chemo and hormones compared with those who got hormones alone.
But there’s a few additional points that we learned from this presentation. One was that although they did better, the low recurrence group of women in this trial still had a very high risk of recurrence; they had a 40% recurrence rate over 10 years. So clearly we need to be working on developing additional therapies that do work in this population. So the implication is that the patients in this low recurrence group, although they didn’t benefit from chemo, still had a significant risk of recurrence. And so we kind of need to find better therapies for those patients. The second thing I want to point out is that the hormonal therapy used in this trial was Tamoxophin, and in this population of post-menopausal women, most likely today many of those patients receive an aromatase inhibitor or the combination of Tamoxophin followed by aromatase inhibitor. So if, you know, given the current practice we would expect less recurrences than the 40% that was seen, but still we need to do better.