Advanced Prostate Cancer
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Percent Free PSA

Anyone know the answer... a man has an RP which fails and goes on IADT (Lupron) which lowers the PSA to <.1....after 12 months of Lupron he goes on the off cycle and the PSA starts to rise...the reading at 18 months out is .1 and at 21 months out it is .3 with a Free PSA reading of 33%..I know Free PSa is useful as a diagnostic tool before a biopsy but what is the significance of a Free PSA of 33% in Metastatic PCa with a PSA of .3 and rising.

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We don't know if free PSA has any significance as there hasn't been much research on this topic. There was a study in 1998 ( that concluded , "Although most cancers exhibit low values of percent free PSA, a significant proportion of aggressive tumors will demonstrate high values. Until this latter phenomenon can be explained, the widespread use of percent free PSA to distinguish benign from malignant disease or to stage confirmed malignant disease should be approached with caution. I am not aware of any other study which examines this question.

Bottom-line: We don't know and I do not believe that you can put any real significance on this one, single small study.




I agree with Joel. But maybe more important is whether you went far enough on the Lupron. Yes, some docs say quit after 12 mo. But an old line guru, Dr. Strum, likes to see staying at 0.05 or lower for 12 months. Big difference...maybe. Also, just eyeballing your two numbers, i'm taking a SWAG at doubling time: <3 mo! Don't want to panic you and these low numbers can be very misleading, but.. And, finally, you are calling it metastatic, but offer no proof--there have been reports of RP leaving behind prostate tissue-benign and/or cancerous. Your report does not say there was salvage radiation treatment; that may be the next step...maybe after a scan to try to find the cancer. (Mine was found in the pelvic lymph nodes after primary radiation treatment.)

herb s.

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Gus, PSA is a protein that has to attach itself to a red blood cell to be measured, as we get our normal PSA numbers---the cancer releases the protein and it then gets attached to the red blood cell. The free PSA, indicates to me---protein antigen floating in the blood, that is not yet attached itself or hooked up with a blood cell. Now that is my understanding. Of course not being a Pca Doctor/Oncologist--I may be totally wrong. But I would not be concerned about Free verses bound--the More total PSA, the more Prostate Cancer cells are active and not asleep.


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