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I think it's a great question! ;) (¯`v´¯).`·.¸.·´ ¸.·´¸.·´¨) ¸.·*¨)(¸.·´ (¸.·´ .·´ ¸ JackieTo: ProstateCancerSupport From: ffioreaz@...Date: Wed, 16 May 2012 21:46:02 +0000Subject: Supressed PSA and PC

Hi all,

This is probably a dumb questions but I'm still learning. I read a lot about PC people using drugs and treatment to suppress or reduce their PSA. Does this strategy suppress the prostate cancer or just lower the PSA number. I know it doesn't cure it. You can have a low PSA and still have PC.

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Hi wuppins.

PSA is a natural substance that occurs in the body to liquify the semen so

that it can swim better. It is produced by the Prostate gland. When the

amount of PSA in the blood starts to rise it indicates something is wrong

with the mechanism. It is akin to the gauge on a steam boiler. It

communicates what is going on in the boiler. PSA when it elevates is like a

gauge of prostate activity. As it rises above nominal levels it communicates

some kind of activity is taking place in the prostate. There are some rare

strains of PCa that do not produce PSA but they are uncommon.

The drugs and treatments are directed at the cancer and the PSA becomes the

gauge (dipstick) of the success ot those efforts. Probably an

oversimplification but my understanding of it.

Prostate Cancer grows by feeding on PSA and if we reduce the supply and

prevent the tumors from uptaking it we can force a remission of sorts.

Rising PSA signals prostatic tumor activity somewhere in the body that must

be evaluated and treated if possible. It seems as with all things prostate,

there are no easy answers. I hope this helped.

" Il faut d'abord durer " Hemingway

Supressed PSA and PC

> Hi all,

>

> This is probably a dumb questions but I'm still learning. I read a lot

> about PC people using drugs and treatment to suppress or reduce their PSA.

> Does this strategy suppress the prostate cancer or just lower the PSA

> number. I know it doesn't cure it. You can have a low PSA and still have

> PC.

>

>

>

>

>

> ------------------------------------

>

> There are just two rules for this group

> 1 No Spam

> 2 Be kind to others

>

> Please recognise that Prostate Cancerhas different guises and needs

> different levels of treatment and in some cases no treatment at all. Some

> men even with all options offered chose radical options that you would not

> choose. We only ask that people be informed before choice is made, we

> cannot and should not tell other members what to do, other than look at

> other options.

>

> Try to delete old material that is no longer applying when clicking reply

> Try to change the title if the content requires it

Link to comment
Share on other sites

Guest guest

:) It sure does. Thank you. (¯`v´¯).`·.¸.·´ ¸.·´¸.·´¨) ¸.·*¨)(¸.·´ (¸.·´ .·´ ¸ JackieTo: ProstateCancerSupport From: ikennedy2@...Date: Wed, 16 May 2012 17:30:20 -0700Subject: Re: Supressed PSA and PC

Hi wuppins.

PSA is a natural substance that occurs in the body to liquify the semen so

that it can swim better. It is produced by the Prostate gland. When the

amount of PSA in the blood starts to rise it indicates something is wrong

with the mechanism. It is akin to the gauge on a steam boiler. It

communicates what is going on in the boiler. PSA when it elevates is like a

gauge of prostate activity. As it rises above nominal levels it communicates

some kind of activity is taking place in the prostate. There are some rare

strains of PCa that do not produce PSA but they are uncommon.

The drugs and treatments are directed at the cancer and the PSA becomes the

gauge (dipstick) of the success ot those efforts. Probably an

oversimplification but my understanding of it.

Prostate Cancer grows by feeding on PSA and if we reduce the supply and

prevent the tumors from uptaking it we can force a remission of sorts.

Rising PSA signals prostatic tumor activity somewhere in the body that must

be evaluated and treated if possible. It seems as with all things prostate,

there are no easy answers. I hope this helped.

"Il faut d'abord durer" Hemingway

Supressed PSA and PC

> Hi all,

>

> This is probably a dumb questions but I'm still learning. I read a lot

> about PC people using drugs and treatment to suppress or reduce their PSA.

> Does this strategy suppress the prostate cancer or just lower the PSA

> number. I know it doesn't cure it. You can have a low PSA and still have

> PC.

>

>

>

>

>

> ------------------------------------

>

> There are just two rules for this group

> 1 No Spam

> 2 Be kind to others

>

> Please recognise that Prostate Cancerhas different guises and needs

> different levels of treatment and in some cases no treatment at all. Some

> men even with all options offered chose radical options that you would not

> choose. We only ask that people be informed before choice is made, we

> cannot and should not tell other members what to do, other than look at

> other options.

>

> Try to delete old material that is no longer applying when clicking reply

> Try to change the title if the content requires it

Link to comment
Share on other sites

Guest guest

Not sure I’d agree with everything

says, if only because he does not make the point clearly that PSA is NOT prostate

cancer specific. Most changes in PSA level are from something other than prostate

cancer. I wrote up a small piece – PSA 101 (see http://www.yananow.org/PSA101.shtml

) which has helped newcomers to start to understand the value and dangers of

using PSA solely to identify and measure any progress in prostate cancer so I

won’t go over all those issues here.

The PSA test was originally developed to

establish if the surgical removal of the prostate gland had been successful. In

broad terms, at that time it was thought that ONLY the prostate gland produced

PSA and therefore if the gland was removed there should be no PSA measurable by

the standard PSA tests in the studies. As time went by, two things

happened – the PSA test was used for diagnosis, although there is no

direct correlation between PSA levels and prostate cancer being diagnosed and

the PSA test was used for checking on the efficacy of other therapies, where

the gland was NOT removed or even totally destroyed and was therefore capable

of generating levels of PSA. Further ultra-sensitive PSA tests were developed

which claimed to measure PSA levels more accurately to more decimal places and

these were again applied to all therapies – there is another piece on

Ultra-Sensitive PSA at http://www.yananow.org/UltraPSA.htm

It was also found that PSA was NOT prostate GLAND specific, as initial thought,

but was also produced by other parts of the body (women for example can have

measurable PSA levels but they do not have a prostate gland).

Apart from the issue of therapies other than

surgery leaving behind prostate gland tissue capable of generating PSA, changed

modern surgery techniques aimed at saving nerves and reducing the probability

of erectile dysfunction can also result in prostate gland tissue being left

behind and this can also generate measurable levels of PSA. So taking all this

into account PSA levels on their own cannot be guaranteed to be associated with

prostate cancer either before therapy or after therapy although such levels may

be useful pointers, more aspects need to be considered before action is taken.

asserts that “Prostate Cancer

grows by feeding on PSA……”. He may be right, but in my

sixteen years since diagnosis I have never seen this put forward as a theory or

demonstrated by studies. There may well have been studies that I have

overlooked, but the general view at present is that it is Testosterone and

specifically DHT – dihydrotestosterone that ‘feeds’ tumours. So

the principle forms of what are frequently termed ‘hormone therapies’

but more correctly are termed ADT (Androgen Deprivation Therapy) are aimed at

reducing the amount of Testosterone produced or the amount taken up into the

gland by the receptors on the cell formations being blocked. In this context

some, or in rare circumstances all, of the prostate cancer cells die off and

cease to produce PSA. These treatments are therefore not directly suppressing

the production of PSA but lead to the death of cells that might be producing

PSA.

There are some therapies and natural

supplements which can reduce the size of a prostate gland. Since a very large prostate

gland – especially one resulting from the common BPH (Benign Prostatic

Hyperplasia) which is not life threatening – can produce large levels of

PSA with no prostate cancer being present, anything that reduces the size of

the gland can also reduce the PSA levels generated by the gland.

Complex? You bet. No simple answers

anywhere.

All the best

Prostate men need enlightening, not

frightening

Terry Herbert - diagnosed in 1996 and

still going strong

Read A Strange Place for unbiased information at http://www.yananow.org/StrangePlace/index.html

From:

ProstateCancerSupport

[mailto:ProstateCancerSupport ] On Behalf Of Kennedy

Sent: Thursday, 17 May 2012 10:30

AM

To: ProstateCancerSupport

Subject: Re:

Supressed PSA and PC

Hi wuppins.

PSA is a natural substance that occurs in the body to liquify the semen so

that it can swim better. It is produced by the Prostate gland. When the

amount of PSA in the blood starts to rise it indicates something is wrong

with the mechanism. It is akin to the gauge on a steam boiler. It

communicates what is going on in the boiler. PSA when it elevates is like a

gauge of prostate activity. As it rises above nominal levels it communicates

some kind of activity is taking place in the prostate. There are some rare

strains of PCa that do not produce PSA but they are uncommon.

The drugs and treatments are directed at the cancer and the PSA becomes the

gauge (dipstick) of the success ot those efforts. Probably an

oversimplification but my understanding of it.

Prostate Cancer grows by feeding on PSA and if we reduce the supply and

prevent the tumors from uptaking it we can force a remission of sorts.

Rising PSA signals prostatic tumor activity somewhere in the body that must

be evaluated and treated if possible. It seems as with all things prostate,

there are no easy answers. I hope this helped.

" Il faut d'abord durer " Hemingway

Supressed PSA and PC

> Hi all,

>

> This is probably a dumb questions but I'm still learning. I read a lot

> about PC people using drugs and treatment to suppress or reduce their PSA.

> Does this strategy suppress the prostate cancer or just lower the PSA

> number. I know it doesn't cure it. You can have a low PSA and still have

> PC.

>

>

>

>

>

> ------------------------------------

>

> There are just two rules for this group

> 1 No Spam

> 2 Be kind to others

>

> Please recognise that Prostate Cancerhas different guises and needs

> different levels of treatment and in some cases no treatment at all. Some

> men even with all options offered chose radical options that you would not

> choose. We only ask that people be informed before choice is made, we

> cannot and should not tell other members what to do, other than look at

> other options.

>

> Try to delete old material that is no longer applying when clicking reply

> Try to change the title if the content requires it

Link to comment
Share on other sites

Guest guest

Thank you Terry. (¯`v´¯).`·.¸.·´ ¸.·´¸.·´¨) ¸.·*¨)(¸.·´ (¸.·´ .·´ ¸ JackieTo: ProstateCancerSupport From: ghenesh_49@...Date: Thu, 17 May 2012 11:40:25 +1000Subject: RE: Supressed PSA and PC

Not sure I’d agree with everything

says, if only because he does not make the point clearly that PSA is NOT prostate

cancer specific. Most changes in PSA level are from something other than prostate

cancer. I wrote up a small piece – PSA 101 (see http://www.yananow.org/PSA101.shtml

) which has helped newcomers to start to understand the value and dangers of

using PSA solely to identify and measure any progress in prostate cancer so I

won’t go over all those issues here.

The PSA test was originally developed to

establish if the surgical removal of the prostate gland had been successful. In

broad terms, at that time it was thought that ONLY the prostate gland produced

PSA and therefore if the gland was removed there should be no PSA measurable by

the standard PSA tests in the studies. As time went by, two things

happened – the PSA test was used for diagnosis, although there is no

direct correlation between PSA levels and prostate cancer being diagnosed and

the PSA test was used for checking on the efficacy of other therapies, where

the gland was NOT removed or even totally destroyed and was therefore capable

of generating levels of PSA. Further ultra-sensitive PSA tests were developed

which claimed to measure PSA levels more accurately to more decimal places and

these were again applied to all therapies – there is another piece on

Ultra-Sensitive PSA at http://www.yananow.org/UltraPSA.htm

It was also found that PSA was NOT prostate GLAND specific, as initial thought,

but was also produced by other parts of the body (women for example can have

measurable PSA levels but they do not have a prostate gland).

Apart from the issue of therapies other than

surgery leaving behind prostate gland tissue capable of generating PSA, changed

modern surgery techniques aimed at saving nerves and reducing the probability

of erectile dysfunction can also result in prostate gland tissue being left

behind and this can also generate measurable levels of PSA. So taking all this

into account PSA levels on their own cannot be guaranteed to be associated with

prostate cancer either before therapy or after therapy although such levels may

be useful pointers, more aspects need to be considered before action is taken.

asserts that “Prostate Cancer

grows by feeding on PSA……”. He may be right, but in my

sixteen years since diagnosis I have never seen this put forward as a theory or

demonstrated by studies. There may well have been studies that I have

overlooked, but the general view at present is that it is Testosterone and

specifically DHT – dihydrotestosterone that ‘feeds’ tumours. So

the principle forms of what are frequently termed ‘hormone therapies’

but more correctly are termed ADT (Androgen Deprivation Therapy) are aimed at

reducing the amount of Testosterone produced or the amount taken up into the

gland by the receptors on the cell formations being blocked. In this context

some, or in rare circumstances all, of the prostate cancer cells die off and

cease to produce PSA. These treatments are therefore not directly suppressing

the production of PSA but lead to the death of cells that might be producing

PSA.

There are some therapies and natural

supplements which can reduce the size of a prostate gland. Since a very large prostate

gland – especially one resulting from the common BPH (Benign Prostatic

Hyperplasia) which is not life threatening – can produce large levels of

PSA with no prostate cancer being present, anything that reduces the size of

the gland can also reduce the PSA levels generated by the gland.

Complex? You bet. No simple answers

anywhere.

All the best

Prostate men need enlightening, not

frightening

Terry Herbert - diagnosed in 1996 and

still going strong

Read A Strange Place for unbiased information at http://www.yananow.org/StrangePlace/index.html

From:

ProstateCancerSupport

[mailto:ProstateCancerSupport ] On Behalf Of Kennedy

Sent: Thursday, 17 May 2012 10:30

AM

To: ProstateCancerSupport

Subject: Re:

Supressed PSA and PC

Hi wuppins.

PSA is a natural substance that occurs in the body to liquify the semen so

that it can swim better. It is produced by the Prostate gland. When the

amount of PSA in the blood starts to rise it indicates something is wrong

with the mechanism. It is akin to the gauge on a steam boiler. It

communicates what is going on in the boiler. PSA when it elevates is like a

gauge of prostate activity. As it rises above nominal levels it communicates

some kind of activity is taking place in the prostate. There are some rare

strains of PCa that do not produce PSA but they are uncommon.

The drugs and treatments are directed at the cancer and the PSA becomes the

gauge (dipstick) of the success ot those efforts. Probably an

oversimplification but my understanding of it.

Prostate Cancer grows by feeding on PSA and if we reduce the supply and

prevent the tumors from uptaking it we can force a remission of sorts.

Rising PSA signals prostatic tumor activity somewhere in the body that must

be evaluated and treated if possible. It seems as with all things prostate,

there are no easy answers. I hope this helped.

"Il faut d'abord durer" Hemingway

Supressed PSA and PC

> Hi all,

>

> This is probably a dumb questions but I'm still learning. I read a lot

> about PC people using drugs and treatment to suppress or reduce their PSA.

> Does this strategy suppress the prostate cancer or just lower the PSA

> number. I know it doesn't cure it. You can have a low PSA and still have

> PC.

>

>

>

>

>

> ------------------------------------

>

> There are just two rules for this group

> 1 No Spam

> 2 Be kind to others

>

> Please recognise that Prostate Cancerhas different guises and needs

> different levels of treatment and in some cases no treatment at all. Some

> men even with all options offered chose radical options that you would not

> choose. We only ask that people be informed before choice is made, we

> cannot and should not tell other members what to do, other than look at

> other options.

>

> Try to delete old material that is no longer applying when clicking reply

> Try to change the title if the content requires it

Link to comment
Share on other sites

Guest guest

Terry said " asserts that “Prostate Cancer grows by feeding on PSA."

Oops. I meant to say testosterone. But that brings me to think what does it feed on when someone who has lost testicular function becomes adt naive and his disease increases?

Dratted affliction!

"Il faut d'abord durer" Hemingway

Supressed PSA and PC> Hi all,>> This is probably a dumb questions but I'm still learning. I read a lot > about PC people using drugs and treatment to suppress or reduce their PSA. > Does this strategy suppress the prostate cancer or just lower the PSA > number. I know it doesn't cure it. You can have a low PSA and still have > PC.>>>>>> ------------------------------------>> There are just two rules for this group> 1 No Spam> 2 Be kind to others>> Please recognise that Prostate Cancerhas different guises and needs > different levels of treatment and in some cases no treatment at all. Some > men even with all options offered chose radical options that you would not > choose. We only ask that people be informed before choice is made, we > cannot and should not tell other members what to do, other than look at > other options.>> Try to delete old material that is no longer applying when clicking reply> Try to change the title if the content requires it

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Guest guest

The theory has two horns: Either the cancer

cells have found a way to grow and multiply without DHT –

dihydrotestosterone OR the other organs in the body which can produce DHT have

upped production levels and are still feeding the cells. But….. the

latter theory tends to be discarded when PSA levels increase and symptoms

develop despite very low Testosterone counts

Who knows, really. Many theories, many

examples of cases falling outside of current theories and studies.

All the best

Terry

From:

ProstateCancerSupport [mailto:ProstateCancerSupport ]

On Behalf Of Kennedy

Sent: Thursday, 17 May 2012 12:33

PM

To:

ProstateCancerSupport

Subject: Re:

Supressed PSA and PC

Terry said "

asserts that “Prostate Cancer grows by feeding on PSA. "

Oops. I meant to say testosterone. But

that brings me to think what does it feed on when someone who has lost

testicular function becomes adt naive and his disease increases?

Dratted affliction!

" Il faut d'abord durer " Hemingway

Supressed PSA and PC

> Hi all,

>

> This is probably a dumb questions but I'm still learning. I read a lot

> about PC people using drugs and treatment to suppress or reduce their PSA.

> Does this strategy suppress the prostate cancer or just lower the PSA

> number. I know it doesn't cure it. You can have a low PSA and still have

> PC.

>

>

>

>

>

> ------------------------------------

>

> There are just two rules for this group

> 1 No Spam

> 2 Be kind to others

>

> Please recognise that Prostate Cancerhas different guises and needs

> different levels of treatment and in some cases no treatment at all. Some

> men even with all options offered chose radical options that you would not

> choose. We only ask that people be informed before choice is made, we

> cannot and should not tell other members what to do, other than look at

> other options.

>

> Try to delete old material that is no longer applying when clicking reply

> Try to change the title if the content requires it

Link to comment
Share on other sites

Guest guest

Thank you all for some very interesting comments. Lot's of made good sense.

>

> The theory has two horns: Either the cancer cells have found a way to grow

> and multiply without DHT - dihydrotestosterone OR the other organs in the

> body which can produce DHT have upped production levels and are still

> feeding the cells. But... the latter theory tends to be discarded when PSA

> levels increase and symptoms develop despite very low Testosterone counts

>

>

>

> Who knows, really. Many theories, many examples of cases falling outside of

> current theories and studies.

>

>

>

>

>

> All the best

>

>

>

> Terry

>

> _____

>

> From: ProstateCancerSupport

> [mailto:ProstateCancerSupport ] On Behalf Of Kennedy

> Sent: Thursday, 17 May 2012 12:33 PM

> To: ProstateCancerSupport

> Subject: Re: Supressed PSA and PC

>

>

>

>

>

> Terry said " asserts that " Prostate Cancer grows by feeding on PSA. "

>

>

>

> Oops. I meant to say testosterone. But that brings me to think what does it

> feed on when someone who has lost testicular function becomes adt naive and

> his disease increases?

>

>

>

> Dratted affliction!

>

>

>

>

>

>

>

> " Il faut d'abord durer " Hemingway

>

> Supressed PSA and PC

>

> > Hi all,

> >

> > This is probably a dumb questions but I'm still learning. I read a lot

> > about PC people using drugs and treatment to suppress or reduce their PSA.

>

> > Does this strategy suppress the prostate cancer or just lower the PSA

> > number. I know it doesn't cure it. You can have a low PSA and still have

> > PC.

> >

> >

> >

> >

> >

> > ------------------------------------

> >

> > There are just two rules for this group

> > 1 No Spam

> > 2 Be kind to others

> >

> > Please recognise that Prostate Cancerhas different guises and needs

> > different levels of treatment and in some cases no treatment at all. Some

> > men even with all options offered chose radical options that you would not

>

> > choose. We only ask that people be informed before choice is made, we

> > cannot and should not tell other members what to do, other than look at

> > other options.

> >

> > Try to delete old material that is no longer applying when clicking reply

> > Try to change the title if the content requires it

Link to comment
Share on other sites

Guest guest

wuppins wrote:

> This is probably a dumb questions but I'm still learning. I

> read a lot about PC people using drugs and treatment to

> suppress or reduce their PSA. Does this strategy suppress the

> prostate cancer or just lower the PSA number. I know it doesn't

> cure it. You can have a low PSA and still have PC.

We've had enough answers, with enough differences, that I thought

I'd weigh in on this and see if I can confuse the issue even

more.

Here is a very long winded dissertation on my understanding of

the PSA and testosterone issues.  I'm not an expert and could

have some of this wrong, but I hope I've got it right and that my

explanations make sense to whoever can stand to read them.

                            About PSA

                            ---------

As I understand it, prostate cells are the primary producer of

the protein known as PSA, or " prostate specific antigen " .  There

are other cells in the body that can produce it (the technical

term is " express " it), but only in tiny amounts compared to what

prostate cells can do.

Prostate cancer tumor cells are mutated prostate cells.  The

mutations they have cause them to divide and replicate when they

should not and, if they become metastatic, to grow in places in

the body outside the prostate where they should not.  But these

tumor cells are still prostate cells and they still, usually,

produce PSA.  So PSA acts as a good measure of the total number

of prostate cells in the body.  If that number is larger than can

be accounted for by the size of the prostate itself, then there

is a good chance that there are too many prostate cells around.

The extras could be benign (called " benign prostate hyperplasia "

or " BPH " ) or they could be out of control, i.e., tumor cells.

There are some things that can cause prostate cells to produce

more PSA than usual.  A prostate inflammation will often do that.

An inflammation might be caused by an infection, by mineral

deposits that accumulate (like kidney stones in the ureters), by

radiation (which is a possible cause of PSA " bounce " after

radiation treatment) or possibly by other causes that are not yet

understood by medical science.

That's the background.  Now to your actual question:

    Does lowering PSA suppress the prostate cancer?

As far as I know, the answer is No, it does not.

As far as I know, there are two ways to lower PSA.  One way is to

change the prostate cells to get them to produce less PSA.  This

might be done if there is a prostate inflammation by using

antibiotics to cure an infection or by using anti-inflammatories.

The other way is to damage or kill off prostate cells.  This is

what the hormone therapies and chemotherapies do.  They reduce

the total amount of cancer cells by killing a lot of them.  It

may be the case that these therapies can make some of the cancer

cells less active, i.e., make them stop dividing and spreading,

without killing them.  I don't know.

But in general I think that we can say that if the PSA goes down

it's because there is less cancer in the body, not the other way

around (i.e., it is NOT that the cancer goes down because the PSA

goes down.)

                       About Testosterone

                       ------------------

Testosterone is a small molecule that acts as a signaling

molecule in the body.  It is largely produced in the testicles

but can also be produced in small amounts elsewhere.  It

circulates in the blood stream.

Prostate calls contain testosterone " receptors " on their

surfaces.  When a testosterone molecule floats by in the blood

stream and collides with a receptor, the receptor grabs it

( " binds " to it) and imports the testosterone molecule into the

cell, where various chemical reactions occur that result in the

prostate cells continuing their healthy (or in the case of tumor

cells unhealthy) activity.

For a very rough analogy, we might think of a tumor cell as being

like a flashlight.  The light has a battery and a switch.

Testosterone isn't like the battery.  It doesn't " feed " the

cancer in that sense.  It's more like the finger on the switch.

The presence of testosterone switches on the activity, including

unhealthy activity, of the tumor cells.

                      About Hormone Therapy

                      ---------------------

Currently used hormone therapies can work in one of three ways:

 1. Reduce the amount of testosterone produced in the body.

    That's done (in an amazingly indirect way) by Lupron,

    Zoladex, and similar drugs.

 2. Block the ability of the testosterone receptors on the

    surface of the prostate cells to bind to testosterone.

    That's done by bicalutamide (Casodex) and nilutamide.  I

    think it's also done by Zytiga and MDV 3100.

 3. Stop or reduce the reactions inside the cells that occur

    after testosterone is taken in.

    That's done by finasteride (Proscar) and dutasteride

    (Avodart).

" ADT2 " uses some combination of two of these.  " ADT3 " , also known

as " triple hormone blockade " , uses all three.

                  About " castration resistance "

                  -----------------------------

Hormone therapy works for a while.  In some men it can work for

many years.  In some men it works for a few months or years.  In

some men it hardly works at all.  Whether it works well or not

has to do with the specific mutations involved in an individual

man's cancer.  These are different for different men.

As far as anyone knows, hormone therapy never kills every single

prostate cancer cell in the body.  Some continue to live in spite

of it.  We don't really know that for absolute certain because

some of the most powerful hormone therapies, e.g., Zytiga, are

brand new and haven't been tested on men whose cancers are very

small and just starting out.  But the current medical assumption

is that hormone therapy is never a complete cure.

Some cells seem to become " castration resistant " .  They continue

to divide and multiply even when testosterone levels are

extremely low.  If so, they will eventually re-populate the body

and the patient will have a big load of cells like this that

don't respond to hormone manipulation.  These tumor cells will

eventually kill him if he doesn't die of something else first.

I know of three theories that have been proposed for castration

resistance:

 1. Tumor cells manufacture more testosterone receptors.

    When a testosterone molecule in the blood stream collides

    with a receptor, the molecule is imported into the cell.  If

    the number of molecules circulating in the blood is reduced,

    a tumor cell can keep up its supply by increasing the number

    of receptors.

    An analogy for this is a cup out in the rain.  In a heavy

    rain, the cup will fill with water but in a light rain it may

    not.  However if we put a big funnel over the cup then even a

    light rain may funnel down enough water to fill the cup.

    There is a lot of evidence that this actually happens.

 2. Tumor cells manufacture their own testosterone.

    Some researchers claim that some tumor cells can actually

    evolve to be able manufacture testosterone without needing it

    from outside.

    I don't know how good the evidence is for this.  It sounds

    dubious to me but, who knows?

 3. Tumor cells may be able to perform the same chemical

    reactions without the presence of testosterone that they

    formerly only performed in the presence of testosterone.

    If we can think of testosterone as a signal that turns on a

    switch, we can imagine a switch that gets stuck in the " on "

    position even without the signal.

I believe that the efficacy of Zytiga and MDV 3100 after other

hormone therapy has failed is evidence in favor of theory number

1.  It is possible that, because Zytiga and MDV 3100 also

eventually fail, that theory number 2 or 3, or both 2 and 3, are

also true, or that there is some other explanations 4, 5, etc.

that I don't know about or that haven't yet been discovered.

I hope that is all accurate and helps.

    Alan

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