Background: Herein, we report a complete response after whole brain radiotherapy (WBRT) and concomitant T-DM1 in a patient with HER2-positive metastatic breast cancer (MBC) and extensive brain and leptomeningeal involvement.
Case presentation: A 46 years old Caucasian woman with HER2-positive MBC and no baseline CNS involvement, started in August 2015 1st line therapy with Pertuzumab-Trastuzumab-Docetaxel, with partial response. However, in April 2016 the patient eventually progressed with emergence of brain and leptomeningeal metastases. Hence, she started in May 2016 2nd line therapy with T-DM1 and concomitant WBRT, with complete response (CR) after 3 courses of therapy, with complete resolution of neurological symptoms and no relevant toxicities. The CR is lasting over 13 months and the patient is out of corticosteroid use.
Conclusions: To the best of our knowledge, this is the first case reporting interesting antitumor activity of T-DM1 and concomitant WBRT in both brain and leptomeningeal metastases, with a favorable safety profile and prolonged extracranial disease control. Further prospective studies should confirm these findings.
Keywords: Brain metastases; HER2-positive; Leptomeningeal metastases; T-DM1; Trastuzumab Emtansine; Whole brain radiotherapy.