Is there a limit to the size of a prostate cancer oligometastasis for SBRT?

I think that, in general, the direct answer to this is 'no'; there is no specific size cutoff that makes SBRT not feasible in this setting. There is some data in other settings that suggest local control is not consistently impacted by the size of oligometastatic tumors, and there is little data to the contrary (i.e., Pacifico et al., PMID 36071292 and Pop et al., PMID 36506614). With that said, many publications have limited the size of oligometastatic lesions, often to <5 cm (i.e., Muldermans et al., PMID 27131082), so treatment of lesions larger than this is difficult to speak to.

What appears to be significantly important, however, is the GTV/PTV dose (i.e., Rogowski et al., PMID 33750437). As such, size may not matter directly, but rat...