Axumin (FACBC) PET-Scan: Specificity? Sensitivity? Anybody?

Greetings!

I'm deeply curious about the effectiveness and particularly the sensitivity of the so-called "Axumin" or fluciclovine-based (FACBC) PET-scan in detecting distant, low-grade metastatic disease relative to other PET-scan methodologies. I've done my research, and that process will certainly continue, but I'm hoping to get some feedback here from experienced (veteran) forum members.

As can be seen in my signature (below), I'm a newly-diagnosed, 'high-risk' guy, with a markedly elevated PSA (68), and fairly soon, I'll likely be undergoing a combined treatment plan involving LDR-BT, IMRT and ADT/HT. However, in discussions with team members (and various other specialists), the topic of potential for "distant metastasis" and its implications for future treatment protocols almost ALWAYS seems to surface, yet we have no evidence of its presence or absence, because all previous CT, bone and FDG-PET-scans have been deemed 'negative'.

So, the question becomes this . . . regardless of cost or insurance authorizations, or typical usage guidelines, or other such secondary considerations, is an Axumin PET-scan likely to offer a significantly greater degree of sensitivity than the standard FDG-based PET-scan for someone in my shoes?

For discussion purposes, I'll add a couple of other key points:

1) The Axumin PET scan has been ordered by my RO at my request (its my choice on whether or not to get it).
2) The Axumin PET scan is FDA-approved, but is typically reserved for 'recurrent' PCa patients, not 'newly-diagnosed'.
3) The Axumin PET scan is typically reserved for PCa patients with relatively high PSA values (>20 ng/dL).
4) The Axumin PET-scan would presumably be quite helpful in preparing a future radiation (IMRT) treatment plan.
5) The Axumin PET scan is unlikely to be authorized by any mainstream insurer.

In summary, given the costs of the scan itself, and the travel involved, should I consider getting this Axumin PET-scan in hopes of getting superior definition or clarification on the presence or absence of 'distant metastases'? Or is this technology likely to be equally disappointing in its results, relative to other previously 'negative' scans, some or all of which could potentially have been so-called "false" negatives?

Decisions, decisions . . .

Anybody?

Thank you!

RobLee said...
Balladeer - the following are the minimum PSA levels for various types of scans I've found online:

PET-PSMA = 0.6 ng/ml
PET-F18 Flurocholine = 1.8 ng/ml
PET- F18 (Axumin) = 2.0
MRI-Feraheme = 2.5
MRI-C11/F18 = 2.5

If you're going self pay, I don't think you'll learn anything new at this point, given your PSA rise over the past year. In other words, it would probably be just one more negative test (I've had plenty of negative tests and none had stopped the cancer from progressing).

As you already have a treatment plan, if a scan were to show any distant spread it might AT MOST suggest including chemo upon the completion of radiation. I have no special knowledge in this area, just stuff I've picked up along the way.

RobLee,

I appreciate your response, and rest assured, your level of technical expertise on the matter doesn't concern me much. If you've had experience with it at all, or you've done some research on it and can share what you've learned from it, then that's all that matters. Its all valuable information.

Just to be clear, I've been leaning towards skipping this Axumin PET-scan from the outset, and for some of the very same reasons that you've outlined here. In all likelihood, I'd be on the hook for the cost of the test itself, in addition to probably another $1,000 or more in net travel costs. But I'd literally 'kill' to get valid, reliable information regarding the existence or absence of potential metastases, if it were possible, for two key reasons: 1) to end the incessant speculation and conversations about whether or not it has in-fact spread to distant areas, and 2) to provide the RO with better information for the pre-op planning and mapping processes associated with beam therapy (IMRT) and seed implantation (BBT).

However, the other consideration here is this . .. My RO is a truly great guy, with tremendous experience, and a very optimistic and agreeable demeanor. So I think in this instance, it may have been a case where I, the patient (a well-meaning, but often forceful, outspoken sorta guy), may have mentioned in passing the 'perceived' utility of such an advanced form of PET-scan, and then, whether he (himself) felt it was warranted or not, he simply agreed to order it, solely to make me happy. That's my guess and it makes even happier to have him in my corner.

And the other downside(s) of proceeding with the Axumin PET-scan, is the fact that I'd have to take a break from my current daily regimen of 50mg Casodex tablets, about one-week prior to the scan, and, I'd need to postpone my first Lupron injection by another 2-3 weeks, neither of which I'd be too tickled about doing. So, I think I have my answer. I think a standard risk/benefit analysis points to a pass on the Axumin PET. But thank you so much for the helpful feedback, and continued best wishes to you on your own journey through the maze.

RobLee said...
We can sometimes overthink things. You and I have corresponded before, regarding HT before or after your vacation (which hopefully worked out okay). I've never had a PET scan so as I said, this is just info I've gathered online. In a way I am somewhat fortunate in that I had to rush into treatment (flew home just days before surgery, and moved out of our house a month later). It would be nice to have had the luxury of time to pick over details. I questioned my RO on treatment options I guess just to sound like I knew what I was talking about. He just went ahead with whatever he had planned for me anyway. So far seems to have worked, though things certainly could have gone more smoothly.

With your pathology I think you don't want to delay treatment any longer. Even if you cross every T and dot every I there's no guarantee that the course will go any better than if you just go with the flow.

Nope, no further delays in-store for me. Its already been too long, and who knows what the consequences of those delays will prove to be, but unfortunately, I (the patient) had virtually 'zero' ability to change those delays or timeframes, most of which were essentially industry driven.

But its all good! The plan moving forward has finally been established and I feel great about it. Casodex now, Lupron in a week or two (after vacation), and LDR-BBT about eight weeks later, followed a month after by IMRT through November or early December. Can't say as I'm looking forward to any of it, but I feel immensely more 'positive' about things now than I have for many months.

Thanks again.

Tall Allen said...
High risk patients can get the DCFPyL scan for free at NIH. Better than Axumin and it's free. I think I already mentioned it to you and gave the contact details.

???? Boy, that doesn't sound familiar at all, and I can't say for certain that it didn't happen, but I'd like to think I would have remembered something that significant. Sorry I missed it, Tall Allen, but could you possibly repost that information or direct me to the earlier thread where you believe that conversation took place? Thanks.

Some may be wondering why high risk patients with clear abdominal CT and bone scans would be looking for additional scans.

It is because the "standard of care" scans are such poor detectors of metastases.

Many high risk patients with clear scans are metastatic. This is precisely why they are at "high risk" of recurrence. Their small clumps of metastatic cells are smaller than the not-so-small clumps that the standard of care scans are able to detect.

There is not consensus whether patients who are metastatic should have treatment to the prostate. Some believe that taking out the source of the cancer improves future treatment results. Others believe that treating the prostate in the face of metastasis is inflicting pain with no gain.

If you are in the latter group, you want the very best information available about metastasis.

BOB 46 said...
. . . Many high risk patients with clear scans are metastatic. This is precisely why they are at "high risk" of recurrence. Their small clumps of metastatic cells are smaller than the not-so-small clumps that the standard of care scans are able to detect.

There is not consensus whether patients who are metastatic should have treatment to the prostate. Some believe that taking out the source of the cancer improves future treatment results. Others believe that treating the prostate in the face of metastasis is inflicting pain with no gain.

Bob,

Thank you for your two postings and for the information they provided.

While I'm geuinely grateful for the added information, I'm compelled to admit that I do not know how to wrap my head around it all. The imperfect nature of the science behind micro-metastasis and its potential for existence, and whether (or how) it can be detected with any degree of certainty, is truly 'mind-numbing'. If we read between the lines of your last posting (and the predictions of most experienced surgeons as well), a 'high risk' patient is bound to have distant metastasis, bound for future recurrence (regardless of treatment choices), bound for eventual failure. And yet, equally experienced radiation oncologists, readily familiar with your own 'high risk' diagnosis, who propose a comprehensive treatment plan like BBT/IMRT/ADT, statistically predict the exact opposite . . . that you're bound for success, bound for survival (>95%). How does the average rational or clinically 'sane' person even begin to reconcile those two completely divergent viewpoints? I (for one), have no clue.

Moreover, I'm beginning to believe that this entire discussion of PET-scan types and their respective efficacies in detecting distant micro-metastases, may constitute nothing but added 'smoke' to a tightly enclosed room, by essentially masking the single-most important point for such 'high risk' patients, which is this . . . would the results of 'thee' most specific, most sensitive, most expensive, most elite PET-scan technology available to anyone, anywhere in the known world, effectively "change" the proposed treatment plan for such a patient in any meaningful way beyond the BBT/IMRT/ADT already established?

For me, THAT is the central question at-hand, and my guess is, that the answer to that question from most trained medical professionals would be a resounding "No"! And so, for me personally, as a 'high risk' guy, and as the guy who actually initiated this thread, its beginning to make the whole business of "diagnostic imaging" a potentially moot point, for anyone diagnosed as 'high risk', at this stage of the game.

Thanks again for your views and your contributions.

Balladeer said...

Tall Allen said...
No problem. You can call Yolanda on Monday

/clinicaltrials.gov/ct2/show/NCT03181867

Excellent! My sincere thanks to you, sir!

P.S. - Looking over the inclusion/exclusion criteria, it would appear that I couldn't qualify for this trial, even if I wanted to, for about three key reasons:

1) I have no evidence of disease on standard imaging (Cohort 2), but I'm not in relapse, I'm newly diagnosed (disqualifying)
2) Participation would delay the "standard of care" treatment (disqualifying)
3) By virtue of daily Casodex tablets, I'm on ADT (disqualifying)

But again, thank you!

Yeah, I'd would have been interested in this scan as well, having recently been moved to G9 by the Epstein second opinion has raised apprehension levels. But, as you note ADT is a disqualifier.

We just continue the battle -- next is my Uriflow test this Friday to make sure brachy boost will be a go.

1) I think you misunderstand their trial. There are two cohorts- one for recurrent men who have to show evidence of recurrence; and another for high risk men,only defined as GS 8-10 or T3/4 or PSA>20. You qualify for the high risk cohort.

2) Participation will not delay treatment. It will help you decide which treatment is best.

3) That is a problem While starting on Casodex may not have any effect on PSMA-based scans like this one, I don't think they would allow you to participate. However, taking Casodex means that all the other PET scans will be useless for you. Casodex shrinks mets, so there is little to no chance that Axumin, C-11 Choline or any other PET scan will be useful to you now. You can only assume that there were no distant mets and proceed with radical therapy.

Balladeer:

Final comments

The viewpoints diverge because at the current level of knowledge, so much is unknown.

I am not promoting or discouraging any path. I just recognized that you are more inclined to research and analysis than most people, and wanted you to have possibly interesting information.

Most "trained medical professionals" (like most people in all areas of human endeavor) have a bias toward applying the methods that they specialize in. Most patients tend to go along when there is no clear evidence to overrule that bias (or even when there is). If you have read widely on the subject of prostate cancer, you will have noticed references to the history of over-treatment, to the detriment of patients. That bias can work against you.

The research quickly resolves to two not-so-simple questions.

1. What is the effectiveness of radiation therapy, when metastatic cancer is present?

2. In quality of life terms, what is the value of avoiding the negative side effects of radiation therapy (varies widely, impossible to predict with precision)?

All studies that attempt to evaluate the effectiveness of radiation therapy on high risk patients are combining into one group cases where metastatic cancer is not present and cases where it is. This is because the current state of the art (pelvic/abdominal CT scans and bone scans) is not precise enough to tell the difference. When the results are published (survival times/probabilities and side effects/probabilities), they generally look promising. Radiation therapies, in aggregate, extend survival on average, with acceptable side effects on average.

What if the survival improvements on average are due solely to the non-metastatic cases and the metastatic cases experience no improvement?

If people in our circumstances were able to have the perfect scan (non-existent) that was able to detect metastatic cancer down to the cell level, and metastatic cancer was found to be present at a low level, what would the recommendations be?

As stated before, some would suggest to take the "triple play" and hope for the best. Others would suggest to avoid the negative side effects of radiation and go with systemic treatment only.

For a long time, radiation treatment was generally considered not to have significant positive effect on immune system response to cancer. Local radiation was not thought to have enough effect on metastatic cancer to justify incurring radiation side effects. Metastatic patients generally received systemic therapy only.

In recent times, there is increased interest in what is called the abscopal effect. The idea is that radiation to the prostate area stimulates activity in the cancer cells and the immune system that collectively results in the immune system attacking cancer cells away from the area where radiation was directed. Things that I have read recently leave me with the impression that the effect is rare/weak without some treatment modifications. Much research is underway to explore whether immunotherapy techniques in combination with radiation can magnify the abscopal effect, and result in an improved treatment for metastatic cancer.

The systemic treatment path now has many possible combinations. Investigations are underway into the many possible combinations of hormone therapy, chemotherapy, and immunotherapy to see if improved treatment regimens can be found.

Until scans for metastasis are much improved and generally available, treatment decisions about high risk patients with clear abdominal/pelvic CT scans and bone scans are based on low-quality information.

Bob,

Wow! You've covered an awful lot of ground here, and I thank you for taking the time to prepare such a concise and thorough summary of things. At one point or another, it seems to have touched on just about every aspect of the topic as it applies to 'high risk' folks like me (us?), and that's a lot for me to cover, but its very important material, so I'm going to try my best to do so here.

You're correct. I am an avid (almost rabid) 'research' oriented sort of guy, with a clear penchant for the detailed investigation of things like personal backgrounds and behavorial histories to purported wisdom, expertise or authority. And it has paid great dividends for me over the course of the past 50+ years, in everything from war and combat to career choices and capital purchases, right down to the selection of a spouse! Discernment is my lifelong little buddy, and I try to take him with me most everywhere I go. In addition, I want to make it very clear before starting-off here that this issue of 'over-treatment' is something I'm very focused on and very concerned about. As a matter of fact, before sending me off on my initial referral to various oncologists, my one and only urologist consistently emphasized the importance of the balance to be struck between treatment/over-treatment/side effects and quality of life issues. So the fact that you've centered on it here is fantastic.

Now, that all said, one of the first questions you've asked here was . . . "What is the effectiveness of radiation therapy, when metastatic cancer is present?" According to modern medicine, by its very own definition, metastatic cancer 'is' deemed to be present in virtually ALL high-risk men, so the effectiveness of RT on such men would presumably be no less than it would be in their low- to intermediate-risk cohorts, making this question essentially irrelevant in my view. In other words, it can't be any less effective than it is in men without metastasis, and such high-risk men 'without' metastasis don't exist by definition.

In your second question, you've asked . . . "In quality of life terms, what is the value of avoiding the negative side effects of radiation therapy?" For high-risk men, this question would again appear to answer itself, since most high-risk men aren't going to pursue an AS (active surveillance) approach, leaving them with only surgery or radiation as viable options, the former of which isn't even available to most high-risk men, and statistics appear to show the latter (radiation) as offering lesser side effects, lesser recurrence and superior long-term survival. In other words, for high-risk men, "avoiding" radiation doesn't even appear to be an option (i.e., no AS, no surgery, only radiation would appear to have promise).

In the next paragraph you stated the following . . . "All studies that attempt to evaluate the effectiveness of radiation therapy on high-risk patients are combining into one group cases where metastatic cancer is not present and cases where it is." Here again, by medical industry definition, metastatic disease is deemed to be present in essentially ALL high-risk men, so in my view, I don't see how there can be a valid splitting into two such groups.

Next-up would be this business of combined (i.e., double- or triple-play) therapies vs. mono-therapies and their applicability or suitability to high-risk men. The preponderance of peer-reviewed scientific articles and other mainstream literature including on-line sources like this discussion forum, appear to support the contention that for high-risk men, treatment plans like the one I'm leaning towards (the so-called triple-play = LDR-BBT/IMRT/ADT) are superior to any single mono-therapy, in virtually all meaningful respects. In fact, I'm not sure that I've seen a published report that suggests or recommends a single or lone mono-therapy of any sort for the treatment of high-risk PCa. I don't doubt that there's one or more out there, but even if there were, the likelihood of it claiming superior outcomes to those published for the triple-play, would seem to be remote at-best.

And lastly, you seem to have indicated in several places throughout your three previous postings that you too have been diagnosed as high-risk, but you have opted not to disclose your particulars in a signature area, which makes it difficult to know just what commonalities (if any) we might have in that respect, but the one thing that would be of most interest to me would be your own chosen treatment plan? For example, have you undergone treatment of any kind as yet? Or are you still in the pre-treatment phase of things like me? If you have undergone treatment, or are soon planning to, I would be keenly interested in your chosen path and specifically why you chose it.

In any event, I don't honestly know what I'll choose to do in the end, but I'll close here by reiterating that I'm most grateful to you for the thoughtful, thorough and clearly informed response, and I wish you the very-very best with your own treatment choices and outcomes going forward.

All the Best

Balladeer:

The choices:

1. The radiation triple play.

2. Systemic treatment only (some combination of hormone therapy, chemotherapy, and immunotherapy) avoiding the negative aspects of radiation treatments, which includes the treatments themselves, the costs, and the side effects.

The choice between them may be affected by the presence or absence of metastasis.

I believe that many high-risk men with "clear" scans are metastatic, but don't concede that all are. I do not find fault with surgeons who behave as if all are. They can't tell the difference any better than anybody else.

It is my goal not to promote or discourage any treatment path, only to provide food for thought.

There is no reason that the choice that I make without

the-information-that-is-needed-but-cannot-be-obtained

should have any influence on anybody else.

Dr. Rossi was correct that there was more PC than my prostate MRI had shown last summer, despite my RGCC labs. He said that if the C-11 acetate scan showed bone and or lymph Mets that the proton treatments would be a waste of time and $$ since it is only recommended whenPC is contained within prostate area. Dr. Rossi saved me. My wife and I called him back to thank him profusely. Other scans were just two MRIs one which started it all with clear PC tumor, and another I did halfway through the Taxotere which showed reduced prostate tumor. Steve

Balladeer said...
According to modern medicine, by its very own definition, metastatic cancer 'is' deemed to be present in virtually ALL high-risk men... Here again, by medical industry definition, metastatic disease is deemed to be present in essentially ALL high-risk men, so in my view, I don't see how there can be a valid splitting into two such groups.

That is just plain incorrect. I think I have pointed out before that you have a mistaken notion of exactly what metastases are. You may have done some research, but you seem to have skipped the basics. There is NO "medical industry definition" that puts high risk and metastatic disease in the same category. "High risk" means localized and potentially curable. "Metastatic" means the cancer has traveled systemically and is therefore incurable. I suggest you learn more about staging before forming erroneous opinions that can be bad for your health.