How do you approach brain SRS for patients currently receiving Trastuzumab deruxtecan with progressive brain lesions?

Trastuzumab deruxtecan is an antibody drug conjugate targeting HER2 cells. This agent has recently been compared to a similar antibody drug conjugate T-DM1 (Kadcyla) and was found to improve disease progression and lower the risk of death for patients with relapsed HER2 metastatic breast cancer (Cor...

In light of recent information from a small European study published by Bartsch et al., PMID 35941372, it appears that this drug has significant activity in the brain with an overall response rate of 73.3%. Furthermore, a higher rate of radiation necrosis (39.1%) has been reported after SRS when don...

Enhertu has excellent intracranial activity against brain metastases from Her2 positive breast cancer. It is rare to see progression while on the drug and if it appears to be the case, I would first review all prior scans to make sure the lesion is indeed new. In case of enlarging met that was previ...

If progressive brain lesion then another option along with local treatment to consider is to change the systemic treatment of tucatinib-based her2u therapy which has a higher CNS response than other agents.