Fig. 1: Synoptic presentation of systemic and local treatments from metastatic disease diagnosis to LM course including T-DXd treatment.

LM leptomeningeal disease, M months. TCHP trastuzumab, pertuzumab, carboplatin and docetaxel, THC trastuzumab, pertuzumab and docetaxel. HP pertuzumab and trastuzumab. Atezo-HP Atezolizumab, pertuzumab, and high-dose trastuzumab. T-DM1 trastuzumab emtansine. GDC0084 paxalisib. Cape capecitabine. WBSRT whole brain and spine radiotherapy. SRS stereotactic radiation therapy. WBRT whole brain radiation therapy. VNR vinorelbine. T-DXd trastuzumab deruxtecan. BrMs brain metastasis. ‡bRT brachytherapy with radioactive seed implantation. † new biopsy showed HER2 in situ hybridization positive, UNK§, patient was given recommendation for further treatment, lost to follow-up; alive at data cutoff.