I don't know if this site has been posted before www.prostate-cancer.org/education/riskases/Strum_StrategyOfSuccess2.html
but it has quite good technical information regarding PCa and PSA. It seems that in general, a prostate's volume (as determined by ultrasound) should deliver an amount of PSA into the bloodstream of 0.066 times the volume of the prostate. A normal average size prostate usually falls between 20cc and 30cc and should deliver a PSA reading up to 2ng/ml. Thus if you have a prostate with a volume of 70cc, then the detectable PSA should be up to 4.62ng per ml coming from normal prostate tissue. If PSA level was 9 then 4.38 ng/ml is coming from elsewhere. According to this site, this excess is suspicious of being tumour based and they have a scale to calculate possible tumour volume. It is interesting that Gleason grade has a marked effect on varying the PSA output per cc of tumour. The higher the Gleason grade the less PSA is produced per cc of prostate based tissue. (stands to reason I guess........the less that tumour cells become less like prostate cells, the less they would do the same things as prostate cells do. i.e. make PSA). Another interesting point is the explanation of why higher Gleason grades present a greater risk of relapse over time. The greater alterations of DNA in higher grade cells (see Ploidy) is associated with PSA relapse following RPP. This answers another question I posed the other day about
the relevance of gleason post RPP. DNA analysis to determine if the cells in the removed prostate have 'normal" DNA structure or "abnormal" DNA are available and indicative of possible later relapse......I wonder why it is not done as a matter of course as a part of the removed prostate pathology results.
The calculator here linked to the site, is also quite good, once you figure out how to use it.www.prostate-cancer.org/tools/software/000PC_Vol_Ver_Strum_2001.xls
Bill. (who is now suffering information overload!)