@beachflyer
You should be aware that doubling time is not that critical when it comes to having your PSA rise after your prostatectomy. If your PSA hits .2 you want to have salvage radiation, You don’t want to wait for it to rise much higher or there are risks involved. 3 1/2 years after my prostatectomy my PSA Rose to .2, I know dozens of other people that have the same thing with different time between surgery and PSA rise. I had 8+ weeks of salvage radiation and had no side effects at all the time, Six years later, I started having some incontinence, but I’ve had radiation and surgery so who knows what caused it. That does not happen to everyone.

Below are the standard set by the American Society of clinical oncology (ASCO) For what to do if you have a PSA rise after a prostatectomy. If your doctor is not aware of this, you might get a second opinion.

From Ascopubs about what PSA to do salvage radiation.
≤0.2 ng/mL:
Starting at this level maximizes disease control and long-term survival. Patients treated at PSA < 0.2 ng/mL achieve higher rates of undetectable post-SRT PSA (56-70%) and improved 5-year progression-free survival (62.7-75%).
Delaying SRT beyond PSA ≥0.25 ng/mL increases mortality risk by ~50%.

0.2–0.5 ng/mL:
Still effective, particularly for patients with low-risk features (e.g., Gleason ≤7, slow PSA doubling time). The Journal of Clinical Oncology recommends SRT before PSA exceeds 0.25 ng/mL to preserve curative potential.

0.5–1.0 ng/mL:
Salvage radiation remains beneficial but may require combining with androgen deprivation therapy (ADT) for higher-risk cases.

This article discusses the above;
https://ascopost.com/news/march-2023/psa-level-at-time-of-salvage-radiation-therapy-after-radical-prostatectomy-and-risk-of-all-cause-mortality/