You could do a PSMA at a PSA of 1.0 and studies show it is 60% sensitive. The likelihood you would have detectable metastatic disease at the low of level is very low. But, if any out of pocket cost to you is not a big issue, it can't hurt. 60% isn't 0% so it could be valuable if something lit up in your pelvis (most likely a lymph node), I would definitely opt for Whole Pelvic Salvage Radiation instead of just prostate bed. I'm sure most doctors just want more info and not more money but 0.2% vs 1%+ the scan is not going to find anything outside the prostate bed. I believe in past years some Urologists didn't recommend salvage treatment until something showed up on a scan. This has completely changed. If you are doing whole pelvic I'm not sure why they would do a PSMA PET if you are < 1.0 PSA unless they would do additional targeted radiation if in the unlikely chance they found any spots outside the prostate bed. It seems the whole pelvic would cover the entire area where it would most likely detect something?

My understanding is yes, your salvage treatment is your 2nd and final chance to eradicate the cancer completely. It's a matter of data combined with expert advice combined with personal preference on how aggressive you want to be with your salvage treatment. Some may be very wary of potential lifelong urinary issues going aggressive when they don't have "bad" post surgical pathology and/or are older and may die from something else. Others may want to risk increased side effects to try to increase the likelihood salvage therapy is curative. It's a tough decision. Because of my young age I believe it's wise to lean towards the modestly more aggressive route.

At 53 years old I had a PSA of 31. Negative bone scan. Negative PSMA scan for cancer outside the prostate. 3+4 Gleason score with 20% grade 4. Cribriform (small) morphology (most Urologists won't even look for this even though it's a risk factor for recurrence), tumor was "medium" size (between small/medium/large) according to my Urologist.

I had robotic surgery by the Chief or Urology at University of Washington/Fred Hutchinson Cancer Care in Seattle. It was 90% nerve sparing even though other Urologists recommended unilateral nerve sparing as the tumor was mostly on one side. My surgeon said he'd make the decision during surgery. He's done over 1,000 of them. My post surgery pathology was good. No positive surgical margins (he got the whole tumor), no seminal vesicle invasion, no extracapsular extension. I did have perineal invasion which is a relatively lower risk factor for recurrence than the other things like positive margins. I did also get extended lymph node removal, think it was 12-15 lymph nodes in my pelvis. None of them had cancer. 90% of nerves spared - my urinary function was 95% back to normal a year later, 80% back to normal 6 months later, Erectile function is about 80% normal, I can get erections but hard to maintain them during sex. A 5mg dose of Cialis makes me as good as I was before surgery (if not a little better lol.)

I had undetectable PSA (< 0.02) for 18 months and it hit 0.02 a year ago. My last PSA was checked at about my 2 year point a little over 4 months ago and it was still 0.02. I have my next one next week (stressful). I am expecting it to be higher but fingers crossed (this is because 0.02 usually is 90% confirmation of BCR but centers use two successive at 0.03 or above as confirmation just to be sure as to not risk overtreatment.) My Urologist said at this rate if it keeps going up it could be 10 years before I reach 0.2. But I will get salvage scheduled as soon as I hit 0.05 or higher. University of Washington doesn't recommend salvage until 0.2. And as I mentioned my Radiologist who I consulted with all along the way when making treatment decisions said no problem waiting until 0.1. I am of the opinion the longer after confirmed BCR you wait the more time for micrometastases to migrate outside the prostate bed. There are no studies that back up any benefit of doing salvage at that low of a level but if I'm only doing prostate bed, being fully healed from the surgery, the only benefit to waiting would be having another couple years maybe of not having a small set back in urinary and erectile function from the radiation.

I will forego ADT with salvage radiation for a couple reasons. Studies have shown it has no to very little significant benefit for people with favorable post surgical pathologies like me and very slow PSA rise. My initial PSA of 31 does technically put me in the "high risk" group but the post surfical pathology findings add a lot more clarity as to your situation. The high initial PSA meant I'd probably have a recurrence but my post surgery pathology means I have a high chance of the salvage radiation being curative with no evidence of cancer on the margins of the removed tissue or in the lymph nodes. The other reason I would forego ADT is I believe personally it starts the cancer on a path of morphing to no longer being androgen sensitive. So I will save the ADT until much later if salvage therapy fails to buy me time in hopes of future more successful treatments being developed.

While I would forego Lupron or Orgovyx or Bicalutamide (forgive spelling errors) during salvage therapy, I am curious about maybe doing a short course of Xtandi during salvage as it has shown even by itself to be more effective than those other drugs. Unfortunately I wouldn't qualify for insurance coverage unless my PSA DT was < 9 months which it looks like it won't be but it could accelerate. Until recently Xtandi was really only used much later in the cancer progression.