Radical idea: drug based prostatectomy

One problem with that is once a the gland goes cancerous, lumpectomies will just leave good cells to get cancerous in time, so why not go for the whole enchilada. bada boom ,bada bing…. you make my dog sing.

kukukajoo said...
Well in theory this would work but what if the cancer has already spread? Then you will still need to target the cancer cells....

The cancer cells are still prostate cells, this would kill them too. The main problem I see is that all the research direction is trying to figure out how to DIFFERENTIATE BETWEEN normal prostate cells and ONLY target the cancer cells. But there is no point to preserve the rest of the prostate once cancerous changes begin.

For example, since cancerous as well as healthy prostate cells produce PSA, if there is some kind of antibody that can target PSA with a drug linked to it, it would kill ANY cell that produce PSA - healthy or cancerous.

This would be the equivalent of a prostatectomy. Except without a knife or radiation.

When I go through research for targeted cancer therapies, it's all about how to differentiate healthy cell from cancerous cells, which makes sense for other cancers but not for prostate cancer. For prostate cancer, there is NO NEED to differentiate between a healthy prostate cell vs a cancerous one - since the current treatment options like surgery or radiation will try to kill the entire prostate anyways - with serious side effects.


The side effects of this would be semen would no longer have prostatic fluid in it, which means all sperm will die once they are out of the body - but I assume some might even view this as a good thing - the ability to ejaculate without pregnancy risk

I think a question needs to be asked - what is the use of the prostate once you already have had kids? How many men would be willing to get rid of the prostate if they won't face ED/continence issues even without a diagnosis of cancer?

I think I am probably not alone when I say, if not for sexual/continence risk, I would have NO problem of getting rid of the prostate - it saves me of all future problems like BPH, PSA testing anxiety, prostatitis, need for birth control, cancer risk.

I think with our current medical paradigm, even if such drugs are discovered, the path would look like this:
PSA testing cycle -> anxiety -> biposies -> anxiety -> diagnosis -> surgery/radiation/hormone -> PSA testing anxiety -> recurrence -> salvage radiation -> doesn't work -> FINALLY use a "kill all PSA producing cells" when everything else have failed.

I think it's much simpler if say, after having kids, we can have a drug that just "kill anything that produce PSA" which will kill the prostate. This drug probably will never be approved since it is so blind and kills healthy prostate cells too, perhaps explaining why no one has researched it.

The only thing that is remotely close to what am suggesting here is this prostate cancer vaccine:
INO-5150
http://www.inovio.com/products/cancer-vaccines/prostate-cancer/

This vaccine generates an immune response toward PSA and PSMA antigen producing cells (which are mostly prostate cells). This is similar to Provenge in its mecanism but much more specific since it is targeting PSA.

This research is another one that targets PSA but provokes an immune response:
http://www.biomedcentral.com/1471-2407/13/195

However, what I am suggesting is using the FIRST HALF of the vaccine mechanism (which consists of antibodies against PSA-producing cells), but replace the SECOND HALF of the mechanism (which is to generate an immune response) with a drug.

This kind of technology exists already as we have the ability to attach drugs to antibodies (Herceptin the miracle drug for breast cancer, is this type of drug). It is basically an antibody-conjugate-drug.

This is exactly like a precision guided missile, where the targeting system consists of the antibody that will try to attach to anything that produce PSA and PSMA (prostate cells whether normal or cancerous). Once it attaches, the drug is released killing that cell.

My mother used to own a biotech company that specializes in antibodies and conjugates, and I talked to her about this, and she said current technology already exists, but drug development is often not about technology, it's more about "why invest hundreds of millions to billions into clinical trials if the regulators would not approve a drug that not cancer-specific but gland-specific, there is no precedence for this".

This is similar to what I am proposing, except it targets PSMA： http://vimeo.com/85947993

We know the antigen (PSA), we have the antibody that targets it already, we have tens of different cancer drugs that can be linked to antibodies, so why are we not linking drugs to the antibody that targets PSA?

Every antibody drug in the pipeline is focused on how its "tumor specific" and does not harm the rest of the gland - which is absolutely critical in nearly all cases - except with the prostate. Imagine if you did this with liver, brain, bladder, colon cancer etc, nobody would ever approve a drug that kills off the entire organ. But this line of thinking does not need to apply to the prostate - we can live without it.

Perhaps I am to naive being the age I am, but evidence points to that modern technology exists to create a "kill anything that produce a PSA" antibody conjugate drug, but it wouldn't be a "cancer" drug, it would be more like a "prostate tissue" drug, and I think that is just not within the normal line of thinking right now and the investment risk is too high.

Post Edited (thunder2004) : 11/17/2014 12:50:29 AM (GMT-7)

good point steve, tho the surgical skill exists to correct that. And any case, immunology appears to be the lost city of gold.

There is research underway to take a very short-lived radioisotope and bind it to the PSMA expressed on the surface membrane of prostate cells. The idea is that you give the patient an infusion of this substance; it bonds to all the prostate cells remaining in the body, gives them a lethal dose of radiation, and then neutralizes itself (through the normal process of radioactive decay) in a day or two before it does any damage to other body tissue. This is under consideration to fight recurrent prostate cancer, not for use in people with an intact prostate, but in theory the approach could be extended. This is in pre-clinical stage now, not even phase I trials so it is years away from av,ilability.

Longo,
The uretha cells are resistant to radiation and are not affected.