The definition of SECOND biochemical recurrence (after prostatectomy AND salvage radiation)

[Tall_Allen]

There is a confusing array of definitions of biochemical recurrence (BCR) after salvage radiation (SRT). I'm not sure that we're ready for a standardized definition yet.

pcnrv.blogspot.com/2019/08/...

[Blackpatch]

Since commencing study of PCa nearly two years ago I have been surprised at the focus on absolute PSA levels in defining thresholds for entering new treatments etc. Absolute measurements of any natural observable are fraught with difficulty - and PSA is worse than most because there are a variety of tests of different accuracies available.

To my mind, there is insufficient focus on PSADT - by going for the time-derivative, a lot of the background noise is filtered out.

I read a great 2008 paper out of Dana Faber noting that short PSADT men gained more from SRT than those with PSADT greater than 1 year - and then around that time all this seemed to fall into a void and researchers hared off in different directions looking at variables that might predict SRT efficacy... it's good to see SPPORT is stratifying men by PSADT and SVI, I suspect this will be yield some very interesting results.

Anyway... I think tracking PSADT through various treatments may be a sound idea, to get some sort of handle on how aggression may be evolving, and how quickly action may be required.

Stuart

[Tall_Allen in reply to Blackpatch]

For FIRST BCR, PSADT is useless because it is not validated for PSAs below 0.1, and most top ROs agree that SRT works best if used before that. MSK requires 3 values to fit to their log model, so if the goal is to find a clinical recurrence as early as possible, that increases the time delay. Also, PSADT has a great deal of variance for many individuals.