Oncology Data Advisor: Welcome to Oncology Data Advisor. Today I'm here with Dr. Valerie Brutus, a Breast Surgical Oncologist at St. Vincent's Medical Center of Hartford Healthcare in Connecticut. Thank you for joining me today.

Valerie Brutus, MD, FACS: Thank you so much for having me.

Oncology Data Advisor: Of course. Tell us about this new technology, Magtrace. What is it, and how does it work?

Dr. Brutus: Magtrace is a magnetic dye, and when it's injected into the breast, it mimics what breast cancer would do. It travels the lymph node that will most likely be affected by breast cancer, if the cancer cells have broken through the milk duct.

Oncology Data Advisor: Which patients are eligible for Magtrace?

Dr. Brutus: It's currently only available for patients who are diagnosed with ductal carcinoma in situ (DCIS), which is commonly referred to as stage 0 breast cancer, for those who require a mastectomy as part of their treatment. The majority of patients who are going to be diagnosed with ductal carcinoma in situ are actually treated with what we call breast conservation, where only the affected portion of the breast is removed with surgery. But there are some patients who are required to have the whole breast removed. Currently, it's only for those patients that Magtrace is used.

Oncology Data Advisor: And what is the significance of this for helping to determine treatment versus surgery and all of those decisions?

Dr. Brutus: The significance is purely with surgery for now. When we do a mastectomy for those patients, the results that we have from their biopsy just tell us that, so far, the cancer is trapped inside the milk duct. When we do further surgery, we don't know what else we're going to find.

Traditionally, the current standard is to inject some dye at the time of surgery that can travel to the lymph nodes underneath the armpit. We remove those lymph nodes at the time of surgery in case the cancer cells have traveled outside the milk duct. With the current dye that we were using before Magtrace, it traveled to lymph nodes, but it only stays in the lymph nodes for less than 24 hours. This is why the lymph nodes were removed at the time of surgery. With Magtrace, this dye stays in the lymph nodes longer, even a few weeks or months.

We can inject the dye in the breast at the time of surgery, perform the mastectomy, and then wait for the pathology from the surgery to tell us what we have. Does the patient still only have stage 0 breast cancer, or does this patient have invasive cancer? If the pathology tells us that the patient only has stage 0 breast cancer, then we don't need to go back to remove some lymph nodes. This patient is spared having those lymph nodes removed. If the pathology tells us on the mastectomy that this patient does have invasive cancer, then we can go back a few weeks after to surgically remove some lymph nodes to dictate more for the treatment, if needed. This is where it's very important. It just allows us to spare patients the additional procedure.

Oncology Data Advisor: That's really exciting.

Dr. Brutus: It is exciting.

Oncology Data Advisor: Since Magtrace also helps reduce the risk of lymphedema, how does this work and what is the significance?

Dr. Brutus: It's because we don't have to remove the lymph node. This is where the risk of lymphedema comes in, because when we perform a sentinel node biopsy, where a few lymph nodes are removed under the armpit, there's always a low risk to have lymphedema. The risk can vary between 5% to 7%. Of course, there are going to be other factors that can make this risk a little higher, but if the patient does not need to have the lymph nodes removed, then we have no risk. This is where Magtrace can help us prevent those patients from having lymphedema, by just allowing us to better select which patients need to have the lymph nodes removed.