A brief discussion on treatment options available for patients with HER2+ metastatic breast cancer and brain metastases who progress on the HER2CLIMB regimen.
Sara A. Hurvitz, MD: This patient gets SRS [stereotactic radiosurgery] to the brain metastases and does change to tucatinib-capecitabine-trastuzumab because her disease is progressing in the lung and brain. She achieves a partial response in the lung, as well as central nervous system responding very nicely. A year later, however, she has new lung metastases, which are leading her to have a cough. Her brain shows stable disease and no new lesions. Sara, how would you approach this patient who’s had stable disease in the brain but is progressing outside the brain and is on the tucatinib-based regimen? How do you choose among the therapies?
Sara M. Tolaney, MD, MPH: In this case, she hadn’t had T-DXd [trastuzumab deruxtecan]. We gave her THP [docetaxel, trastuzumab, pertuzumab], and she went straight to tucatinib. This is where T-DXd [trastuzumab deruxtecan] comes into play because she’s got systemic progression and stable CNS [central nervous system] disease. You did smartly throw in the issue that she’s got symptomatic lung disease and a cough. But as Bill pointed out, this is the exact patient that needs a response in the lungs to clinically improve. Therefore, I’d feel comfortable using T-DXd [trastuzumab deruxtecan] here.
Sara A. Hurvitz, MD: Bill, if this patient was stable in the lungs and progressing in the brain on tucatinib-capecitabine-trastuzumab, what would you do?
William J. Gradishar, MD: It would depend on what prior therapy the patient had to the brain. The fact that systemic therapy is well-controlled gets back to the question of whether radiation—in the form of additional SRS or whole brain—might be the preferred therapy. I’d be inclined to talk to my radiation oncologist before jettisoning the treatment plan that seems to be holding the systemic disease stable.
Sara A. Hurvitz, MD: Excellent. Sara, when do you bring surgeons into the discussion? Are they involved in the multidisciplinary management of brain metastases from the outset? Is there a tumor board?
Sara M. Tolaney, MD, MPH: Yes, for all our brain metastases cases, we have a tumor board that does review the cases with surgery and radiation oncology, but the surgical piece comes in certain situations. One is when there’s such bulky disease that you have midline shift. If you’ve got an occluded ventricle or a high ICP [increased intracranial pressure], those are situations where surgical intervention becomes unquestionable—it’s at a critical point where you must intervene. Sometimes, when you have just 1 brain metastasis, this issue comes up. Is it worth resecting oligometastatic disease if that’s the case? Is there survival benefit from doing surgical intervention? At this point it’s hard to know because we’re so good at doing really focal SRS. Sometimes we consider surgery and radiation in those rare oligometastatic cases where there’s no other anatomic reason they need surgery.
Transcript edited for clarity.