@fritzo I am not aware of a similar nomogram prediction on recurrence after radiation treatment. I think such a nomogram would be more difficult to create because there are so many radiation types (IMRT, SBRT, LDR brachytherapy, HDR brachytherapy, and combinations of these) along with various time lengths of ADT involved. As an example, in my own case I had 26 IMRT sessions, one HDR brachytherapy session and one year of ADT.

The side effects from an RP are harsh, immediate, and often long lasting. Those of us choosing radiation as a primary treatment want to avoid those severe side effects and typically choose an aggressive radiation plan such that the odds are good that primary radiation is the only treatment we will need for life. But even if that didn't happen, as @brianjarvis mentioned there are numerous treatments that can follow radiation if need be, even radiation itself. SBRT can be used as spot radiation multiple times where ever needed. All the focal therapies can be used on metastatic spots as well. What can't be done twice is wide area radiation across healthy tissue that has already been radiated. But a recurrence after radiation as a primary treatment is not likely to need that. And if a systemic treatment were needed for a recurrence after radiation as a primary treatment, there are the new drugs like Nubeqa and new procedures like Pluvicto. According to @jeffmarc there are also numerous new treatments under development right now that will be even better than what we have today. As such, I think it is an outdated knock on radiation as a primary treatment that follow-up treatments are limited.

And yes, joining the Inspire cancer forum is very worthwhile. It allows for lengthy blogs as you can see mine here https://www.inspire.com/m/williamwattsmith/about/