Posted 4/28/2014 12:48 AM (GMT -6)
HDRIDER QUOTE: "I've also read (here on this forum), that cancerous prostate cells can give off much more PSA than benign normal cells relative to their volume. Benign cells give off .66 PSA per cc and G6 can give off as much as 3 or 4 PSA per cc."
HI HDRIDER, - One of the dangers of the internet, including Boards such as this one, is that information posted is often accepted as "fact" when, actually, the information is inaccurate. Then, it gets repeated from a memory that cites their source as "I read (or heard) it somewhere". In fact you DID read it on this Board, and so did I, in a Post from an often-credible source on some PCa subjects,
BUT, in this case, whether due to a typo or an incorrect understanding, the conversion factor of .66 contained in the quoted Post above is erroneous and should NOT be perpetuated.
The Prostate Cancer Research Institute (PCRI) states that: " - - - gland volume in cubic centimeters (cc) multiplied by 0.066 yields the amount of PSA produced by the benign-related epithelial cell population of prostate cells." - - - and this is the original source of this calculation by Medical Oncologist Stephen Strum, MD.. But Dr. "Duke" Bahn, another touted PCa "expert", reportedly promotes 0.1 per cc of tissue volume as the appropriate multiplier, but PSA is not an exact science and so both are approximations. This range of .066 to 0.1, however, is probably a pragmatic basis for such calculations and is helpful in estimating the amount of PSA usually attributable to normal benign tissue in an individual elevated PSA reading. Obviously, the proper placing of the decimal point is CRUCIAL to accuracy in such calculations.
The LIKELY cause of any additional PSA yield must then be attempted to be determined, with the full recognition that the other two main sources, other than PCa, would likely be cells affected by BPH (Benign Prostate Hyperplasia or Hypertrophy (natural benign growth with advancing age) and/or Inflammation, which is known as Prostatitis. Any of the 3 sources, or all three, MAY be contributors to any excess PSA present. At the present time, direct examination of Biopsy tissue samples by a qualified Pathologist, is the ONLY widely accepted method of identifying PCa, although advancing imaging can sometimes identify "suspicious" lesions, they need to be confirmed by Biopsy to legitimize an individual Prostate Cancer diagnosis.
Re: Reported “ZERO” PSA
TECHNICALLY, there is no such thing as a real zero reading. Each and every PSA assay (test) has a known limitation to its sensitivity, below which readings are not reliable. This reliability threshold varies with the individual assay used, but exists in each.
ACTUAL results, if any, below the reliable sensitivity level of the assay involved, are usually reported as LESS THAN (<) the specific known limitation. In the Standard PSA test, this is usually 0.1 ng/ml (<0.1), but there is at least one that is 0.2 ng/ml. Hyper-sensitive and Ultra-sensitive PSA assays have sensitivity reliability that can go as low as 0.01 and/or even 0.001 ng/ml (not taking into account electrical interference=”noise”) that can sometimes artificially alter such highly sensitivity results
This said, the casual term "zero" is often used in the verbal reporting of a result when it is below the stated reliability thresholds, even though, TECHNICALLY, it is not the actual reading, which would contain the < icon, before the numerical identification. The term "undetectable" is even more often used as a substitute for the actual reading but, obviously, that meaning varies with the sensitivity of the result, as does it’s clinical significance.
There is only one way to get a formal, printed "zero" report, and that would be to employ an assay material with sensitivity that is below the amount actually reported. Example: If I would use an assay with sensitivity to 0.001 (1/1000th) to OBTAIN my PSA reading, but only REPORTED to 1/100th of a nanogram it would read 0.00, BUT technically, that would not accurately report the true reading actually obtained.
As you can see, this gets quite complicated and such broad terms as "undetectable" can mean different things to different individuals. Generally, it refers to "CLINICALLY" undetectable, which is WIDELY accepted to be anything LESS than 0.1 (<0.1 ng/ml) in the routine monitoring of post-surgical PCa patients, although certain exceptions are possible in individually advanced cases.
I appreciate this is a lot of explanation for something that is mostly inconsequential to patients who have had successful treatment results, but to those that are interested in the technical determinations and their true meaning and significance, I hope it has been both explanatory and beneficial.
I feel that of the confusion in accurately addressing this disease is often a direct result of NOT knowing and/or UNDERSTANDING the subtle differences found in communicated PCa terminology. - John@newPCa.org (aka) az4peaks