Patients with HER2-positive advanced breast cancer frequently develop brain metastases. Dual anti-HER2 therapy significantly prolongs survival in previously untreated metastatic disease. However, no safety data exist on the concurrent use of pertuzumab, trastuzumab and brain radiotherapy. We describe two cases of previously untreated HER2-positive breast cancer and brain metastases, who developed acute cerebral toxicity during the concomitant administration of anti-HER2 therapy and whole-brain radiotherapy. Systematic clinical data is warranted to prove the safety of this association.

(BELG J MED ONCOL 2018;12(1):22–25)