What systemic therapy would you consider, if any, for an isolated but multifocal CNS recurrence of HER2+ HR negative breast cancer treated with local therapy (>4 lesions treated with resection and SRS)?

There is not an agreed-upon standard approach, nor am I aware of definitive data supporting one approach over another. My preferred approach to managing isolated CNS relapses that are treated locally with no visible systemic disease is to do trastuzumab plus a TKI with no chemo (like EGF104900 regim...