Rules to play by.
Top Line: The most current ASCO guidelines on the treatment of brain metastases are here to usher in the new year.
The Study: First up is surgery, which continues to be recommended when deemed a safe option for large symptomatic brain mets with apparent mass effect, particularly when there is any question regarding primary histology. Basically everything else gets radiation. Radiosurgery is the strong favorite for <5 mets, and is a “reasonable” alternative to whole brain radiation (WBRT) for 5 or more mets, excluding small cell lung cancer (SCLC). When delivering WBRT, both memantine and, interestingly, hippocampal avoidance (in the setting of no hippocampal lesions, of course) are recommended when life expectancy is >4 months. A new twist is when, if ever, to defer radiation with the prospect of starting a potentially intracranially-effective systemic therapy. Let’s back up for a second: it’s never wrong to proactively treat asymptomatic brain mets (ok, unless death is apparently imminent). But now there is—albeit weak—consensus to consider observing small asymptomatic mets until progression when a patient will be starting for the first time newer generation EGFR- or ALK-targeted therapy for non-small cell lung cancer (NSCLC), pembro for PDL1+ NSCLC, ipi+nivo or dual BRAF-inhibitors for melanoma, or tucatinib for HER2+ breast cancer.
TBL: A few new guidelines to familiarize yourself with when treating brain mets include the use of hippocampal avoidance with whole brain radiation as well as scenarios when it is ok to observe when starting new targeted therapies. | Vogelbaum, J Clin Oncol 2021