HER2-Positive Breast Cancer - Episode 13

Case 3: HER2+ Breast Cancer With Brain Metastases

Carey Anders, MD, presents a case that focuses on a patient with HER2+ breast cancer and brain metastases.

Sara Tolaney, MD, MPH: Let’s turn to our next case, which focuses on a patient with brain metastases, and Carey, I can turn to you to present that case.

Carey Anders, MD: On the heels of the last case, unfortunately, particularly in the ER [estrogen receptor]-negative, HER2-positive space, we’ve seen, even with a past CR [complete response], CNS [central nervous system] recurrence. I’m curious if you have seen this phenomenon in your clinic. It’s pretty devastating.

Ingrid A. Mayer, MD, MSCI: It’s not super common, but it’s not uncommon.

Carey Anders, MD: It’s not uncommon, and you would think that with a past CR, it just continues to speak to HER2 predilection to the brain and a sanctuary site. Moving on to this third case, this is a 53-year-old woman diagnosed with metastatic breast cancer 4 years prior. At that time, the pathology showed a grade 3 invasive ductal carcinoma, ER-, PR [progesterone receptor]-negative, HER2 3+ [score] by IHC [immunohistochemistry], and the staging was a T3N0. Imaging at that time also showed metastatic disease, 3 liver lesions, with the largest being 3 cm, and 1 small 1-cm lung lesion. At that time, the brain MRI was negative for metastasis. This was biopsy proven at that time, all ER/PR-negative, HER2-positive, so de novo T3N0M1 disease. The patient went on to the CLEOPATRA regimen with taxane, trastuzumab, pertuzumab, followed by trastuzumab, pertuzumab alone at the completion of the taxane phase. She did have some grade 2 diarrhea and achieved a partial response in both the liver and lung. And then at about the 18-month mark, she had extracranial disease progression with 2 new lung metastases and transitioned to T-DM1 [trastuzumab emtansine], again achieving a partial response. We’re now 12 months out from the T-DM1. The CT of the extracranial disease is stable, but the patient comes into the clinic and has some intermittent dizziness, and a brain MRI is performed with suspicion for brain metastasis and does confirm 2 brain lesions, with the largest 1 cm.

Sara Tolaney, MD, MPH: Carey, how does your thinking—maybe it’s changed over the last year and a half since we’ve had new agents come into play here—but how would you think about treating this patient? Is this someone, for example, for whom you would think about a local therapy approach and maybe return to your systemic treatment, or would you change systemic treatment here, and how would you make that decision?

Carey Anders, MD: I am quite a purist when it comes to the ASCO [American Society of Clinical Oncology] guidelines, and in this setting, the patient has extracranial disease stability, low burden disease in the brain. The one caveat there would be the location in the brain. But a radiosurgery approach to these 2 small lesions, the largest being 1 cm, would be very reasonable. I would have to see the films, I don’t know that I would feel strongly about a biopsy in this setting. If they were radiographically consistent with brain metastasis and not another process, I would feel comfortable with radiosurgery, and then maintaining the T-DM1, particularly if the patient’s tolerating therapy well, and they may have many months of continued disease stability before needing to transition to the next agent.

Transcript edited for clarity.