Do you recommend holding tyrosine-kinase inhibitors for extracranial metastases being treated with SBRT?

In general, yes I would recommend holding TKIs during SBRT. Anecdotally from both my own experience and others, there is a small risk of severe pneumonitis in patients on concurrent or recent TKI (much of this with osimertinib which has a reasonably high risk of symptomatic pneumonitis on its own) although based on the retrospective data we have thus far, I wouldn't say we have strong evidence to say holding TKI actually reduces this risk. Smith et al., PMID 36923158 published a series of 16 patients demonstrating a high rate of symptomatic pneumonitis with concurrent osimertinib and SBRT (56% G2+, 37.5% G3+, 6.3% G4, 0% G5). Notably, all patients in the series with G3+ pneumonitis had tumors within 2 cm of the PBT. Additionally, the 2 pati...