How do you approach a local failure with a rising PSA following prostate SBRT?

I would obtain an MRI if not already done to help delineate local disease extent. A variety of salvage options are available (RP; HIFU; cryotherapy; and re-irradiation with brachytherapy or focal SBRT). A recent systematic review and meta-analysis of local salvage therapies was published by a group from UCLA (Valle et al., PMID 33309278), which did not find significant differences in recurrence-free survival among these approaches; however, re-irradiation (particularly HDR brachytherapy) seemed to have lower toxicity compared with RP.