There surely is a correlation between time to recurrence and PSADT, but it would be interesting to see this plotted out fir a large sample of men post RP.
I suppose PSADT can change over time, but as a start the plot described above would be of interest.
Because PSA<0.2 cannot be used to calculate PSADT, PSADT can't be used to predict BCR.
What about a retrospective study looking at the correlation between TTR and eventual PSADT, ie when PSA reaches 0.2 or higher?
I'm not sure what you're asking for. Men are usually offered salvage radiation by the time PSA reaches 0.1 or 0.2. What is your PSA?
Do you have a literature citation that states PSA<0.2 cannot be used to calculate doubling time?
It is only valid for PSA > 0.1. Look it up for yourself.
I can't find anything online. Do you have a citation?
I'm sure you can find it- or just trust me.
No offense, but I like to validate what I hear by finding multiple sources.
This seems to question Tall_Allen's statement: ncbi.nlm.nih.gov/pmc/articl...
Sure, but it would still be interesting to see how tight or loose the correlation is, even without stratifying for these many variables.
My understanding combining maths and published studies is this: For a two decimal points PSA values discard anything bellow or equal to 0.03. Two reasons for this a) the accuracy is poor and b) the rounding error is high ( 50% from 0.02 to 0.03). For the latter the 20 accepted variance is reached at the transition of 0.05 to 0.06. By then, a very crude doubling time can be estimated. Twice this doubling time and the 0.2 threshold is breached. QED
Are you using ultrasensitive PSA values (< 0.1) for PSADT calculations? You will then overestimate your risk of recurrence. Agreement between PSADT calculated using ultrasensitive vs standard PSA is poor. Ultrasensitive PSADT is often significantly more rapid than traditional PSADT. Ultrasensitive PSADT has no prognostic value.
Having read all these replies, it appears there may be some confusion.
Rib is simply asking if men who have quick BCRs and prone to have high PSADTs down the line. It would seem almost certain that there is such a correlation, though apparently no one's invested the time to make such a retrogressive study.
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