Is it acceptable to use SBRT for prostate bed RT?

In my opinion, this should not be done outside of an IRB-approved research study. We are beginning to see some published experience with moderate hypofractionation in post-prostatectomy patients, which would indicate, at least preliminarily, that this approach may be safe, although the optimal dose per fraction or total dose using this approach has not been established. I am not aware of published data using SBRT in this setting. Even in patients with an intact prostate, there is little long term complication data using SBRT, and as a wise mentor once told me, late effects occur late. In the post-prostatectomy setting, accurate target definition remains a challenge, given that in most cases we really do not know exactly where the tumor lies...

No

As the first author on one of the toxicity analyses of one of the trials in this space, I would not recommend prostate bed SBRT for salvage RT off-protocol at the current time.

Yes, prostate bed SBRT reirradiation is reasonable under certain highly selected cases, preferably on protocol and with pathological confirmation, after informed signed consent.