PSA question

AstroNerd- I am no expert, but I believe they test for psa after Prostatectomy to see if the prostate cancer migrated to another part of your body. Not likely, if your margins were clear.

take care

Actually...PSA is not only prostate specific...it is an antigen that is produced by the glands...the prostate produces the most however...but there are other glands that will produce PSA as well...just at levels so low that only the ultra-low 3rd generation asseys can detect. You body after surgery will seek a new level of PSA...generally below the .1 mark and most likely below the .01 mark. Like strawberry man said...it is used to watch for any escaped PCa cells that may be leaked out through the blood and taken root somewhere else in your body and below detection levels at the moment. Most of the time this won't happen...but it can and you will be tested for the next five years or longer just in case they become active enough to grow large enough that a second treatment is required. The PSA is used to determine how rapidly they are growing and determine if treatment is even needed.

Well just a bit of clarification...prostate cells are actually gland cells which produce a detectable amount of PSA. While normally it doesn't leak psa into the blood system except in very small quatities, but when they turn cancerous they will leak large amounts. So each cell that is cancerous leaks a tiny amount of antigen into the blood. The more cells that leak into the blood stream, they more likely it will be picked up on the assey test. So if you have some cancer cells that have migrated or were left behind during the surgery...there may not be enough of the cancer cells leaking psa into the blood stream to be detected. But as cancer cells multiply then there can be enough of them to be able to measure the psa level. How long it takes for just one cell to multiply into enough cells to measure the psa is determined by how aggressive the cancer is...hence the doubling time...how long it takes for them to double in quantity. This often will take years before they have grown significantly to be detected. Funny thing about cancer cells...they don't die...they just keep on living, unlike normal cells that die and get replaced with new healthy cells. So when the cancer cells don't die they form tumors and continue to multiply and can be monitored by the psa blood levels.

As LV-TX has so eloquently said all prostate cells produce PSA and some of it leaks into the bloodstream. When you are a child the prostate gland is quite small (even in relation to your size). When you hit puberty the size of the prostate increases to about walnut size (about 20 grams or 20cc). On average it remains this size for about the next 30 years and leaks very small amounts of PSA into the bloodstream. On hitting middle age it is common for the prostate to begin growing again sometimes resulting in problems urinating. (it can hit sizes larger than 100 gms or 100cc). Of course this increase in size produces a corresponding increase in the amount of PSA leaked into the bloodstream. All prostate tissue, including cancerous tissue, produces PSA. Cancerous prostate tissue usually leaks a greater volume off PSA than healthy tissue. So later in life the problem becomes .....is that PSA increase due to an increase in size of a relatively healthy gland or is there tumour growing within the gland. To complicate matters further a benign prostate infection will also cause more PSA to be leaked but this is usually a temporary issue. Once the prostate is removed then the production of PSA is essentially stopped with the following exceptions. (a) There are a couple of other glands which can produce very minute amounts of PSA: (b) A small portion of healthy prostate tissue can be left behind which will continue to produce PSA (this can easily occur with nerve saving surgery where a little tissue can be left attached to the nerves) or (c) the tumour may have escaped the prostate ( even microscopically) into lymph nodes, surrounding tissue or distantly and thus will produce increasing amounts of PSA if it survives and continues to slowly grow.
Bill