In what situations will you defer SRS for newly detected brain metastases in a patient with an oncogene driven malignancy?

We have deferred RT only in situation where there is open clinical trial (we had one with oral Her2 new agent for asymptomatic brain metastases and there are other ongoing studies). Outside of a clinical trial, we offer RT upfront rather than waiting for response from systemic agent.

I would and do consider holding off on SRS if a patient has a small asymptomatic lesion without significant edema. I would recommend very close active surveillance.