I had two positive surgical margins after my RARP in December 2018: 4mm at distal apical margin and 1mm at bladder neck margin. The former was in an area of Gleason pattern 4, which for me was cribriform architecture, and the latter had been cauterized. At that time, there was the option to wait to see if salvage radiation would be indicated by a future PSA rise or to elect to have immediate adjuvant RT (ART). Given that my Decipher Biopsy score was 0.94 and that cribriform PCA cells tend to be prolific, I chose ART to my prostatic bed (I think that they recommend some lymph nodes now). Perhaps having a Decipher test of your surgically removed prostate would give you more information for decision making?

I believe that current protocols would lean towards PSA monitoring to two digits after the decimal point and then to have early salvage RT (eSRT) to prostate bed and some local lymph nodes. That's what a friend was recommended and had last year. Probably delays experiencing side effects while still being effective -- quality of life factored in. Your surgeon should have more information and be able to offer options, and you can always seek a second opinion.

FWIW, I ended up with BCR about 2.5 years after the end of ART, but had a great 2.5 years where I ran a marathon and did a century ride on a recumbent road bike.