Post-RP usPSA was between <0.006 and 0.1. 4weeks after to 0.0769

Going by your PSA alone, I would say you need to keep a close watch on the number. You may be familiar with the fact that the American Society of clinical oncology (ASCO) recommends you have salvage radiation when your PSA hits .2. Yours is rising pretty fast, Good to see you’re getting monthly blood tests so you know what’s really going on.

It’s very common for the PET scan to be negative after a prostatectomy and a rising PSA. That’s why they recommend salvage radiation because the most likely place for metastasis growth is in the prostate bed and lymph nodes in that area.

I’m going to post the ASCO recommendation so you know what to plan for. Your doctor probably follows that guideline. 16 years ago, at 62, I had a prostatectomy, 3 1/2 years later, it came back, my PSA was rising, and when it hit .2 I was given a six month Lupron shot and two months later had Eight weeks of salvage radiation. In My case that only lasted about two years. Turns out I have a genetic problem of BRCA2 so my cancer keeps coming back.

Have you had genetic testing? You had prostate cancer pretty young and it could be due to genetics. You definitely should get hereditary genetic test testing. It’s covered by insurance.

From Ascopubs about what PSA to do salvage radiation after a prostatectomy.
≤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/

Dear @jeffmarc Thank you very much for your prompt and thoughtful reply. I really appreciate you taking the time to share both your personal experience and the current evidence regarding early salvage radiotherapy.
Your comments about the timing of salvage treatment and the rationale for proceeding despite a negative PSMA PET scan are very helpful. I will continue to monitor my PSA closely with regular testing and discuss the appropriate timing of any intervention with my treating team.
Regarding genetic testing, I completely agree with your point. I am scheduled to undergo hereditary genetic testing in the near future, and I hope the results will provide additional information to help guide both my management and my family's risk assessment.
Thank you again for your valuable insights and for sharing your journey. I wish you all the very best with your ongoing treatment.