what exactly causes the decrease of PSA plus other questions for inquiring mind

I understand that hormonal treatment as well as chemotherapy and other treatments for PC stage 4 would cause a decrease of PSA. Just wondering if the drop of PSA is due to lymph nodes shrinking, lymph nodes disappearing, bone mets removed (and if so, is this permanently). Does hormonal treatment hit the lymph nodes first or ?? Is there a correlation between percentage of decrease with time needed for decrease of PSA and prognosis? Why can't someone's PSA level drop to undetectable?

[Magnus1964]

You have asked the central questions concerning Pca. All Pca cells produce PSA where ever they are in the body. Killing them decreases PSA.

[Tall_Allen]

Systemic therapies kill many cancer cells (both micrometastatic and detectable) but there will always be some resistant ones. PSA is a good indicator of effectiveness and a lower nadir is prognostic for longer survival. Most detectable metastases put out a lot of PSA. Treating metastases when there are only a few that are detectable treats PSA, and in some cases, PSA can reach undetectable levels for a time. But, unlike systemic therapy, it is unknown if there is any survival benefit to doing that.

[JimVanHorn]

I was told that hormone treatment tells your pituitary to send a hormone throughout the body that stops the production of androgens (Testosterone). Prostate cells (both normal and cancerous) release an enzyme that the PSA test tests for when a prostate cell multiplies. Each prostate cell has a spot on the cell membrane called an androgen receptor (AR). When an androgen comes near to the AR it starts the cell to subdivide into 2 cells. So if you have no androgens the PCa can not subdivide. There is no way to know for sure what cells are subdividing to make a PSA test result, it could be anyone of them. But having a very low PSA means that the cells are not forming tumors. When a cell goes to a bone it sits there, sinks into the bone, leaves a pock mark, and if there are no androgens it is stuck there. Eventually it will die off. Most androgens are in the testes but they are also formed elsewhere like in the adrenal cortex. Lupron can stop androgen production unless you are androgen resistant patient, resistant to Lupron. Your oncologist will help you with that. I hope this helps you understand.

[Racer26 in reply to JimVanHorn]

Very very good

[Hidden]

Thank you all for your help. He goes see the MO tomorrow afternoon. So praying that his PSA will decrease from 20.