Improving Outcomes in Patients With HER2+ Metastatic Breast Cancer: Applying Evidence to Clinical Practice - Episode 8

The Role of the Radiation Oncologist in the Treatment of HER2+ BC and Brain Metastases

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Key opinion leaders in the management of breast cancer discuss the role of the radiation oncologist in treating patients with brain metastases.

Erika Hamilton, MD: Ryan, how do we involve the radiation oncologist? At what points do you think it’s important for a radiation oncologist to see our patients [who] may have metastatic disease?

Ryan Jones, MD: Recognizing my own biases, I would say [that] as we talk about these patients with brain metastases, we would like to be involved as soon as you know a patient has brain metastases. It gives us a bit of pause to think of just drug alone when we have effective local therapy, particularly stereotactic radiosurgery [SRS]. Whole brain has its issues with local control long term, but radiosurgery does quite well. As we’ve seen in our region, at times, it’s even checking the images, looking at the quality of the MRI [magnetic resonance imaging], [and] giving feedback to the imaging center saying, “Hey, we can get a much better quality MRI to establish a true baseline for this patient over the number of lesions.” That’s something we’ve done a lot of work on in our region over setting standards for the kind of MRI images they’re acquiring and getting nice high-quality images for us. In the event the [patient] needs radiosurgery, we’ve got them. The imaging center is trained on that and for follow-up. We like to be involved, if you know of anybody with brain metastasis.

Erika Hamilton, MD: I think you bring up a good point, though, that different specialties sometimes feel differently. Part of the HER2CLIMB [study] [NCT02614794]—you could enroll patients [who] had brain metastases as long as they were less than 2 cm and asymptomatic. You could go larger [than] that if you talked to the medical monitor. I had a patient [who] just wasn’t going to do radiation. She refused. I don’t recommend doing this all the time, let’s be clear, but she had a 4-cm brain lesion. She didn’t do radiation and it ended up less than a centimeter on drug.

Ryan Jones, MD: Then we can take care of the drug-resistant clones.

Erika Hamilton, MD: There you go.

Tiffany Traina, MD: It’s a multidisciplinary partnership. This reminds me of a patient [who] just recently had multiple experiences with SRS [and] had whole-brain [radiotherapy but] kept progressing within the brain. [They were] on [trastuzumab deruxtecan] and did beautifully. [They] then had what looked like progression and went to the [operating room], and it was just all necrotic material. These drugs are powerful. I give credit to our neuro-radiologists, because it’s challenging to interpret what’s going on in the brain.

Rita Nanda, MD: This [issue of] radionecrosis vs disease progression [is something] we all face.

Erika Hamilton, MD: That can be problematic for trials, too, because a lot of trials may not want progressive brain metastases, so you end up with [fewer] options for your patient. Ryan, what about palliative radiation? When do you make the decision for a painful spot or something like that? When do you think it’s reasonable to radiate those? What’s your threshold?

Ryan Jones, MD: I try not to be a hammer seeing a nail in the sense of if you can control it with oral opioids or pain regimen. Then if they’re approaching a new systemic regimen, I try to pause and see [whether] they’ll get the relief they need. I want to get ahead of sites encroaching on the spinal canal. I don’t want this patient coming back paralyzed or [with] some neurologic deficit in a few weeks. In that sense, it can be like [a] prophylactic palliative [approach] at times, depending on the lesion. [I] try to carefully select [without] just treating any painful site if they’ll be starting a new systemic regimen. If it’s progressing on the regimen and they’re not planning a change, then by all means I would treat for pain relief.

Erika Hamilton, MD: Absolutely.

Transcript has been edited for clarity.