Would you consider SRS of non-progressive, stable intracranial lesions while treating with SRS for a single progressive brain metastasis after previous WBRT for multiple brain metastases?

An interesting question and clinical scenario. My default advice for this situation would be to focus on the progressive metastasis only to achieve treatment related goals for local control and symptom palliation (while reducing treatment related toxicity) and reserve further SRS to the additional lesions when (and if) they become symptomatic and/or enlarge. I am not directly aware of any data suggesting that early intervention for stable lesions would be superior to continued clinical and brain imaging observation in such a scenario.

However, one situation where I may consider more comphensive SRS would be in an oligometastatic situation (with 3 mets or less at the time of WBRT). In this scenario, if a patient had received WBRT alone (instead of SRS or SRS/WBRT for oligometastatic brain cancer) and was then subsequently found to have one progressive lesion and one or two additional lesions on imaging followup, one may be able to justify the use of SRS boost to all lesions completing therapy analagous to the RTOG Andrews study (RTOG 9508). The clinical benefits for such split course treatment would be uncertain but one would expect better brain control in this situation than WBRT alone.