I have a key interest in this topic also and had a discussion with my MAYO uroligist last week. He said the key for him is doubling time. Less than one year and he will get agressive with treatment. Additionally, Dr. Stolz from the PCRI, states in one of his video that 10% of men have prostate cancers that are not detectable on PSMA PET scans. You would find his YouTube video very helpful!