Just want to pass on something my doctor told me today at my appointment. I asked him if CgA was a useful test to determine if someone has neuroendcrine differentiation and to my surprise he said "No". He told me that he has seen many patients with normal CgA who had neuroendocrine differentiation. It is often elevated, but not often enough to be useful as a screening tool. I had thought otherwise and was disappointed to hear this.
He said that once it's been determined through a biospy, he will check CgA level to see if it's elevated. If it is he will use it as a tumor marker either in place of, or in addition to PSA as a check for progression.
By the way, my doctor is a specialist in prostate cancer and very knowledgeable. I always try to learn whatever I can when I go in for appointments. Thought I'd pass it on to the forum.
I agree. There should be a combination of indicators, including Chromogranin A, synaptophysin, and neuronal specific enolase. An IHC analysis of tumor tissue is the only sure way.
Thank you Gregg for passing this useful information.
I also asked him about these non-metastic castrate resistant patients who now have Apalutamide, Enzalutmide and will soon have Darolutmide. I thought the number of these patients was very small, but he corrected that. He told me that non-metastatic refers to those who show no metastases with only bone scan and CT scan. So of course, that would raise the number significantly since the sensitive scans are not used for the determination. I wish I could spend a few hours in these appointments.
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Great info. Here is a link to a post written by a med onc who specializes in prostate cancer which speaks to your reply above: prost8blog.com/2019/04/09/w...
Just wondering why are you asking about neuroendocrine PC. I posted about low PSA and growing tumour in neck a couple of days ago. A suggestion was it might be NEPC. However my MO says does not think so as not growing aggresively. I asked for Chrogranin A as per Nalkrats advice. MO said there can be false positives but we can see if elevation or not. Cannot biopsy because of dangerous position in neck. Have not seen any posts on those with NEPC and the symptoms, speed of tumour growth etc. Im zapping this one with stereotactic radiation in a couple of weeks.
You talked about switching to Enzalutamide a while ago when Zytiga fails but there appears cross resistance is set up so maybe 20% chance or so Enzalutamide will work for a few months after Zytiga. I am looking for ways to resensitise Zytiga when my PSA goes up eg. prednisone to dexamethasone switch, BAT, Indomethicin or just maybe a natural product such as Quertesin.
I was asking because there have been some recents posts about neuroendocrine PCa, yours was one and there was at least one more. I have tried to research these tests such as CgA, but it was never that clear to me how useful they were. The articles talked about how they were markers for neuroendocrine cells in general, but not a lot about specific prostate cancer cells. One of the problems for sure is specificity. A lot of cells that are normal produce these substances. My doctor seemed to be more concerned about false negatives, but I never asked about false positives so they are probably there too. But as your doctor said, you can check to see if there is an elevation.
Unfortunately, you need a tissue sample under the microscope to know for sure, but if that's not feasible you can probably get a pretty good idea from other things. Just the fact that you have low PSA and progression, it should be suspected. I would also want to do imaging of the sites where it normally might metastasize such as the lungs, liver and brain.
Here's an article on the subject that also covers all the markers for neuroendocrine PCa.
On the subject of Xtandi, there is cross resistance as you noted. There is some evidence that chemotherapy can rensensitize you to Zytiga.
Have you done any genetic testing for mutations like BRCA1, 2 or ATM?
You're welcome. Right now I'm very lucky to have a PSA that is undetectable wth ADT and Zytiga so when I go in to see my doctor I use my time to learn more, often asking about topics that have been recently posted. I asked him how many patients he has on Zytiga and he said "about 2 dozen". I would imagine he has a lot of patients. He said he was trained by Dr. Pan at UC Davis. He's fairly well known around here in Northern Cal.
My husband has Neuroendocrine PCA. His PSA was normal before diagnosis.. but his Chromagranin was very high. His doctors use a combination of PSA, Chromagranin and CT and Bone scans to monitor.
Since my husbands initial cancer was found in the hip.(hip fracture caused by the cancer) Until the doctors did a biopsy of the prostate, the cancer was a cancer of unknown type... The cancer met to the hip was so "deformed" that the pathologists could not determine the type of cancer. Our oncologist sent my husband in for a prostate biopsy after hearing about his prostate issues for the previous year. This biopsy is what gave us the diagnosis of Neuroendocrine PCA.
If I remember correctly our oncologist said that sometimes the cancer cells become so dedifferentiated that they stop producing the tumor markers.(Chromagranin, PSA ..etc). This was why they could not tell what type of cancer was at the hip.
(That is why they use scans also to monitor his disease)
Thanks for the information. I really apreaciate when people share specifics about what their doctors say about these things. I find that information really valuable, worth a lot of research time.
I asked my MO about testing for CGA and he said that the test is to unreliable. Then I asked about adding NSA test with the CGA to get a better understanding of the nature of the PCa. He again said no and that the only reliable way to determine if your cancer is neurocrine is with a tissue biopsy. At that time ( a month ago) I was still classified as non-metastatic HRPC. I just received results of MRI, CT and BS. I have bone mets to several ribs and one spot on my spine. Also a soft tissue mass near one rib. Iguess he can have the mass biopsied now. i se my MO next week to see where go from here.
It's such an important diagnosis because it will effect what treatments you take. I can see why you want to be 100% sure. I think CgA and NSE are raised in many of these cases, but it would have to be every single one to be useful. I've been through one bone biospy already so wouldn't be looking forward to that, but then you do what you need to do.
I would think soft tissue has got to be better than going into bone. I saw the needle before they stuck it into my bone, then I think my eyes must have gotten really big. "That's the needle you're going to stick into me?" I asked. The doctor responded, "It's more like a drill."
Had one done recently and indeed it sounded just like my Makita drill.
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It's like a dentist appointment on steroids.
When my GP told me I was going to need a bone biospy, I was thinking "Oh Shit!" I asked her what it was like. She said: "Well, it's not pleasant" The bigger problem for me was the next few days. Had a lot of swelling. I used to worry a lot more about things like this. You get through it like everything else.
To further complicate it I had a vagal response and they had to use Narcan to counteract my low BP and heart rate. Little did I know that Fentanyl is used in the sedation. Whole experience was not fun and I don't get the results because it is part of a clinical trial.
And of course you said: "SURE, no problem!"
It's so easy for them to say: you have to suck it up. What specifically are they looking for in the biopsy?
As much as we have discussed the blood tests not being 100%, if biospy is just out of question for you, you could look at all the markers for neuroendocrine differentiation and use a circulating tumor cell test for mutations. It might give you good enough idea without doing a biospy, just a thought. Apparently some work has been done identifying NEPC through circulating tumor cells. Here's one article on the subject, there are probably more if you search.
Thanks for the update. Was there any discussion with your doctor regarding tumor mass vs. prostate biopsy and the differences between the two? I've tried to look that up and didn't find anything.
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