In today’s podcast, we’ll discuss some of the new research that was presented at the 2017 San Antonio Breast Cancer Symposium, held December fifth through ninth in San Antonio, Texas. This podcast will be led by Cancer.Net Associate Editor, Dr. Erica Mayer.
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In today’s podcast, we’ll discuss some of the new research that was presented at the 2017 San Antonio Breast Cancer Symposium, held December fifth through ninth in San Antonio, Texas. This podcast will be led by Cancer.Net Associate Editor, Dr. Erica Mayer. Dr. Mayer is a Senior Physician and medical oncologist at the Susan F. Smith Center for Women’s Cancers/Dana-Farber Cancer Institute, as well as an Assistant Professor in Medicine at Harvard Medical School.
ASCO would like to thank Dr. Mayer for summarizing this research.
Dr. Mayer: Hello, this is Dr. Erica Mayer from Dana-Farber Cancer Institute in Boston. I like to share with you some of the highlights in breast cancer advances from the 2017 San Antonio Breast Cancer Symposium. This was a very exciting meeting this year, with lots of thrilling news in breast cancer research, as well as some of the first snow in San Antonio in the past decade.
First, just a reminder that breast cancer is divided into 3 main categories determined by the presence or absence of receptors on the outside of the cancer cell. These categories include hormone receptor positive, HER-2 positive, and the so-called triple negative, when those 3 main receptors are negative.
It has been an amazing year for breast cancer research, and we saw presentations of breakthrough trials in each of these all major subtypes.
First, I want to review results of research focusing on early breast cancer, meaning breast cancer that is stage I, II, or III, and has not spread in the body.
One topic which has been of great interest for patients with hormone receptor positive HER-2 negative breast cancer is how long to take adjuvant endocrine therapy, meaning pill medications such as tamoxifen or aromatase inhibitor that block estrogen from stimulating breast cancer cells. Over the past several years, there have been research reports suggesting extension of therapy from 5 years up to 10 years may be a preferred option for cancers with greater risk of recurrence. However, longer duration therapy means potentially more long-term side effects, making this a more nuanced decision. An important trial addressing this question was presented at San Antonio, called ABCSG 16. In this trial, patients who already completed 5 years of adjuvant aromatase inhibitor were subsequently randomized to receive either 2 more years of aromatase inhibitor, meaning 7 cumulative years, versus 5 more years of aromatase inhibitor, meaning 10 cumulative years. Results from this trial showed no difference in rates of cancer recurrence for those who received 7 total years versus 10 total years, but did indicate a slight increase in toxicities such as bone fracture, in those who had longer duration therapy. I think this is an important study because it provides more choices for patients in the clinic, as we often say one size does not fit all for choices in treatment. This trial is important as it suggests that for some patients, stopping adjuvant endocrine therapy after 7 years may be adequate, and extension up to 10 years may not be necessary for every person. However, for a person who tolerates this therapy well, has stable bone density, and perhaps has a higher risk of breast cancer recurrence, extension to 10 years can still be pursued. And of course, 5 cumulative years of therapy remains very appropriate for patients with lower risk of cancer recurrence.
Now, moving on to metastatic breast cancer, for patients with metastatic breast cancer, we saw exciting data about new targeted biologic therapies. One important trial presented was the phase 3 EMBRACA trial, which studied the new drug Talazoparib, an oral medication called a PARP inhibitor, in patients who had metastatic breast cancer and who also have a BRCA1 or 2 gene mutation. Patients in the trial were randomized to receive either Talazoparib or a doctor choice of standard chemotherapy. Patients who received the new medication, Talazoparib, had almost twice as long control of their cancer versus those who received chemotherapy, including some patients with very resistant disease. Additionally, no new or serious toxicities were seen in people who received the Talazoparib, and patients receiving Talazoparib had a better preserved quality of life compared to those who received chemotherapy. Now, Talazoparib is very similar to the recently FDA approved PARP inhibitor drug, olaparib, and potentially may be more potent. It is hoped that the data from the EMBRACA trial will lead to FDA approval of this new medication for patients who are known to have a BRCA1 or 2 gene mutation, and who have metastatic breast cancer.
Additional exciting presentations evaluated a novel class of medicines, called antibody drug conjugates, for HER-2-positive and triple negative subsets of breast cancer. Antibody drug conjugates use antibody technology to precisely deliver tiny amounts of potent chemotherapy exclusively to cancer cells, while sparing the rest of the body from chemotherapy-related toxicity. One of these new drugs, which is currently called DS-8201, is being studied for people with HER-2 positive breast cancer. It functions in a very similar fashion to the FDA approved medicine known as Kadcyla or TDM 1. Data was presented from a small early study of DS-8201 in patients who had metastatic HER-2 positive breast cancer who had had many prior therapies, including prior treatment with Kadcyla. In the trial, a majority of patients experienced tumor shrinkage with exposure to this new drug, and almost all the patients experienced some disease stability. This is exciting data, and larger studies with this agent are ongoing.
For patients with triple negative breast cancer, development continues for a drug called IMMU-132, which now has a name, and is known as as sacituzumab. Updated data from an ongoing study using this drug showed notable activity in people with metastatic triple negative breast cancer who had already had several prior treatments, and may have had some resistance to therapy. A large trial is opening now which will evaluate whether this agent should receive FDA approval.
Moving on, in addition to the clinical trials of new medicines, there were very interesting presentations regarding additional options to help support treatment in breast cancer patients. One great topic of interest was interventions to help reduce joint discomfort and stiffness in patients receiving aromatase inhibitors. Certainly, if longer duration adjuvant aromatase inhibitors is preferred for many breast cancer patients, the more we can do to relieve side effects is crucial.
A clinical trial was presented looking at acupuncture as a potential treatment. Patients in the trial were randomized to receive either true acupuncture, versus sham acupuncture, meaning the wrong type of needles were inserted into the wrong parts of the body, versus no acupuncture at all. Results from the study showed that patients receiving true acupuncture had significantly less joint pain and stiffness compared to those who received sham acupuncture or no acupuncture at all. This is really an exciting finding, as it shows a non-medicine option is helping patients receiving aromatase inhibitors. Hopefully, this is an intervention which may allow people to be more adherent to their medicine, stay on their medicine longer, and thus get more benefit out of it.
Another study of interest investigated a method to help preserve fertility in young breast cancer patients who are receiving chemotherapy. This study was a meta-analysis, meaning a grouped analysis of several smaller trials that were looking at giving medicine to temporarily put ovaries to sleep while a woman was receiving chemotherapy for her breast cancer. This treatment called “ovarian suppression.” In a meta-analysis, combining several small trials together provides greater power to answer research questions. In this meta-analysis, the women who underwent ovarian suppression were significantly more likely to get their period back by 2 years after completion of chemotherapy, and were almost twice as likely to have gotten pregnant, versus those who did not undergo the ovarian suppression during chemotherapy. Importantly, the treatment appeared to be safe, as there was no difference in breast cancer recurrence rates whether or not a woman pursued ovarian suppression. In general, ovarian suppression is not for everyone, and it still is considered somewhat experimental, but it is hoped based on this new data, that it will become a more routine option for younger breast cancer patients who are interested in fertility preservation.
Well, that’s it for the quick update from San Antonio 2017. Overall, we continue on a fast track in breast cancer with many new and exciting therapies being actively studied, and research helping support our patients do better than ever before. Stay tuned to Cancer.Net for future updates from upcoming breast cancer conferences!
ASCO: Thank you, Dr. Mayer. Learn more about breast cancer at www.cancer.net/breast. And for more expert interviews and stories from people living with cancer, visit the Cancer.Net Blog at www.cancer.net/blog.
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