Treatments thus far in my bio, but summary is RP in April 2019 (pT2N0M0) and then 6 month Lupron & salvage radiation to prostate bed January 2023. PSA <0.01 in January as expected with T=23, April showed T=176 (low normal), PSA < 0.01, and now in July T=281, PSA = 0.02.
My RO stated "...while that PSA number is not perfect (undetectable), it is not out of the ordinary. PSA is an 'imperfect test', and your next check in 3 months could well be undetectable; we have seen that happen. You should not be concerned at this time."
I want to not be concerned and I do trust my care team, but color me a perfectionist; it has been my understanding that any PSA after an RP is not the best news, though it may also be non-treatable news as well in that "it's a data point, more data is needed to determine if treatment changes are warranted". I do know that my current numbers fit that description.
My question to y'all is this: I understand anecdotally that PSA fluctuations occur (n=1, everyone is different and all that), but are there any studies that indicate PSA measurement variability after RP & salvage radiation where "PSA bumps" occur and PSA eventually goes back to undetectable? A follow-on question is what variability exists for the PSA test, really? (I've only ever used the same lab - Duke U.)