The best results are frequently after you have had salvage radiation. Here is some information about the importance of getting treated in time, starting with .2. it seems to imply that you are at the point that you need to make a decision right away.

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.