Case 2: Risk Factors for Brain Metastases in HER2+ Breast Cancer


Ruta Rao, MD: Let’s talk in general about brain metastases. What are some of the known risk factors for brain metastases in patients with breast cancer?

Komal Jhaveri, MD, FACP: What we have learned is that the risk of brain metastases is high. It’s higher for our patients with a triple-negative breast cancer, and Dr Tolaney had mentioned that the risk is about 50% for our patients with HER2 [human epidermal growth factor receptor 2]– positive disease, and 50% will have it. It remains an unmet need for these patient populations. We’re thinking about this with more lines of therapy and heavily pretreated patients in the ER [emergency department], and we’re thinking about it sooner because there is a higher prevalence of brain metastases in patients with HER2-positive and triple-negative breast cancer.

Ruta Rao, MD: Can you comment on whether, in your institution [Memorial Sloan Kettering Cancer Center], you use a multidisciplinary team to manage these patients with brain metastases?

Komal Jhaveri, MD, FACP: Yes, we do. It depends on exactly how the patient has presented. Was this an incidental finding from an MRI [magnetic resonance imaging] that was done for a particular symptom? We’ll start seeing that more patients are going to get MRIs done based on the current data. Are these patients who presented with a symptom and were found to have a mass affecting an isolated lesion or fewer than 3 lesions of no more than 3 cm in size? We’re thinking about how we get involved and get our neurosurgeons involved. Is this patient appropriate for up-front surgery? Is this a patient who has multiple brain metastases and would benefit from whole-brain radiation therapy? Are there no more than 3 of no more than 3 cm in size? Can we do stereotactic radiosurgery [SRS] for these lesions? Are there active lesions ongoing? Can we offer SRS for more than 3 lesions? That’s an active area of research. Yes, a multidisciplinary way of treating patients is the way to go here because we want to engage the right folks and the right team, if not all of them, when we have a patient diagnosed with brain metastases.

Ruta Rao, MD: Dr Tolaney, we’d love to hear from you about a multidisciplinary team and about how you continue current systemic therapy vs switching in a patient who has progression in the brain.

Sara Tolaney, MD, MPH: Like Dr Jhaveri, we are all interested in making sure that we get a multidisciplinary consult when someone has brain metastases. We [at Dana-Farber Cancer Institute] have a multiclinic that involves neuro-radiation oncology as well as neurosurgery. They would be seeing us in addition to the medical oncologist. It is extraordinarily helpful. I’m constantly emailing our neuro-radiation oncologists for help along the way. It is critical to work as a team to make decisions because it’s hard for me to know, for example, for a patient who has had prior SRS, can they get more SRS for their progression in an area that’s near that? I can’t make those decisions without consulting them and getting their thoughts. It is critical in managing our brain metastases patients, to work very carefully with this team.

Then to your other questions about what to do if someone has controlled systemic disease vs progression at this time in the brain and what to do. The guidelines have said that if someone has systemically controlled disease but progresses in the brain, then one should consider local therapy to the brain and return to the systemic drug that the patient was on. It wouldn’t be an indication to change systemic therapy. If someone has progression both systemically and in the brain, then we think about whether they’re a candidate for local therapy and switching systemic treatment.

It brings up a question: Should there be a shift in our guidelines now that we have tucatinib available? There is survival benefit for patients with brain metastases, so do we need to change to tucatinib in someone who has brain metastases but has otherwise systemically controlled disease? We don’t have sufficient data to know that. For now, I would generally continue my practice. If someone had a focal area in their brain that could be treated with SRS, but the patient was systemically stable, then I wouldradiate and continue their current therapy.

Transcript edited for clarity.

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