I can see how the discussion on this blog can get a little confusing for many men. The Prostate Doc has attempted to write a brief overview that provides a very basic level of understanding, and he (probably appropriately) avoids too many details which, in reality, makes the simplistic perspective too complex for a short blog intended for a general audience. I’m not saying that the Prostate Doc doesn’t understand these differences (because of course I think he does understand them), I’m just saying he’s simplified things for the sake of a general audience.
The reality is that there have been many discussions here at HW which have been more in-depth than this high-level blog, and so many readers here will recognize the blog shortcomings. I think the blog does provide a decent overview for men who know just-a-little about PSA after surgery…which is a lot of guys. Not everyone wants to get into the hairy details, and not everyone needs to, and the target audience for this blog was not those with considerable patient knowledge of PSA and PSA testing.
You’ll notice that the Prostate Doc does make mention of the ultrasensitive PSA test down at the end of his 3re paragraph, “With the advent of ultrasensitive PSA…”, so it is important to realize that everything above there is talking only about the standard PSA test (lower detection limit of 0.1ng/mL).
The comment made by BB_Fan is exactly correct, that some benign prostate tissue left behind, especially after nerve-sparing surgery, can frequently be detected…with the ultrasensitive test down to a lower detection limit of 0.01ng/mL (typically). This is the original use of the term "PSA Anxiety" for guys getting the ultrasensitive test and seeing the naturally occuring variation of benign tissue. The standard test won't pick-up benign traces because it is almost always below the standard test lower detection limit.
If PSA is detected with the standard test after RP, this is a typical indicator of systemic (persistent) prostate cancer. If there were only local PC left in the prostate bed after surgery (not systemic mets), then the PSA would typically (not always) be initially below the standard test detection limit, but increase over time to become detectable.
Many here have been getting the ultrasensitive PSA test, and it is often prescribed if there are unfavorable pathology outcomes or high clinical risk cases…but these situations are not covered in the Prostate Doc’s blog.
I hope this helps clarify…