So my Father's PSA has risen whilst on Zytiga and after switching to Dexamethasone. Although that switch from Prednisone did it bring it down for two consecutive months.
My father had a recent PSMA scan which shown multiple bone mets but shown the cancer does express PSMA.
Am I correct in thinking that AC225 is a better choice for bone mets?
And does anybody have any information on whether it would be better to do this treatment before chemotherapy?
This study here on chemotherapy naive patients yielded excellent results.
Ac 225 PSMA treatment is mostly indicated in patients with bone metastases and diffuse infiltration of the bone marrow. If there are bone metastases without diffuse infiltration of the bone marrow he could be treated with Lu 177 PSMA instead of Ac 225.
Ac 225 has the problem that it could cause permanent damage to the salivary glands (xerostomia) which could have a significant negative effect in the quality of life.
I believe there are anecdotical data suggesting that these treatments could be more effective if the patients did not have chemo.
There are places in Germany doing Ac 225 and Lu 177 PSMA treatments (combo or tandem treatments) trying to reduce the negative effects of Ac 225 on the salivary glands.
Yes, a PSMA PET/CT (Ga 68 or 18F DCFPyl) could indicate if there are bone metastases and diffuse infiltration of the bone marrow. He coud have multiple bone metastases without diffuse infiltration of the bone marrow.
Ac 225 (alpha particles) have more ionizing power than Lu 177 PSMA (beta particles). Alpha particles travel a very short distance (0,1 mm in biological tissues) meanwhile beta particles may travel around 3 mm in the same tissues. If the patient has diffuse infiltration of the bone marrow using Lu 177 PSMA may affect whatever bone marrow is left because of the distance the beta particles can travel.
I assume, he does not have diffuse infiltration of the bone marrow since it was not reported by the radiologist. He could be treated with Lu 177 PSMA which has less side effects and see what happens.
They could always stop Lu 177 PSMA if it is not working and treat him with Ac 225 PSMA.
If he wants to pursue these treatments , he would have to select a place in Europe, Australia or South Africa and pay for the treatments.
I went to the Technical University of Munich in 2016. I had Lu 177 PSMA treatment. The only side effects I had was some fatigue for about 24 hours and some edema which resolved with one pill of Lasix. One Lu 177 PSMA treatment took care of all the lymph node metastases I had in the pelvis and abdomen.
There is no data that one is better than the other for bone Mets, or that either is better than Xofigo for that purpose. We have more data on Xofigo. Alpha emitters like Ac 225 and Ra 223 have more killing power but shorter range
There may be no data, but I can give you my personal experience so far.
I have taken 2 infusions of Lu-177 and the only tumors (mets) that have reduced in size are the lymph node mets. The bone mets have either increased in size or some have stayed same. A lot of new bone mets have appeared after the two treatments.
I therefore conclude that Lu-177 is better for lymph node mets than for bone mets.
Very definitely so in my case. A few others have also confirmed the same to me.
The top US groups, like NCCN, disagree. That's probably because cost is not a factor in the US recommendation, as it is in the EMA recommendation. In fact, data show that Xofigo seems to be most effective when the bone met burden is low. We have comparatively little data on the PSMA-based radiopharmaceuticals, whereas Xofigo has been the subject of several major randomized clinical trials, and has post-marketing data as well.
This year, the US FDA has warned that Xofigo should not be combined with Zytiga, but follow-up research suggests that the combination has not been problematic when bone strengthening agents have been used. Of course, there have been no combination or sequencing trials done yet for the PSMA-based radiopharmaceuticals.
I have no idea if your experience with LN mets will turn out to be true across a wider population. But if that is the case for you, Xofigo would be the preferred radiopharmaceutical for you, given that bone mets are associated with a worse prognosis than lymph node mets.
I just discussed Xofigo with my doctor and he told me he has not been impressed at all with it. Then I talked to him about AC-225 and he said once that gets approved and they work out the problems, he thinks Xofigo will be obsolete.
I think I just learned something from your last response.
Thank you very much for the dope on Xofigo as well as Ac-225. I sort of sensed it myself. I must clarify though that 15 months into reading this board, I still consider myself an ignoramus on PC matters, though about 10% better than earlier when I didn't even know what PSA meant
I also liked the saying : Never teach a pig to sing. It wastes your time and annoys the pig Thanks.
How about this one : Arguing with a stranger on the Internet is rather like trying to play chess with a pigeon. It knocks the pieces over, takes a shit on the board and then struts around in triumph
"My father had a recent PSMA scan which shown multiple bone mets but shown the cancer does express PSMA."
1. How can a PSMA scan show cancer other than that which expresses PSMA?
2. LU 177 and especially AC225 can damage your kidneys and/or your salivary glands. Living life on dialysis may be worse than the prostate cancer in terms of quality of life issues. And loss of salivary gland function may be even worse than dialysis regarding quality of life issues.
I think they are experimenting with new PSMA ligands where this might no longer be an issue. But the new PSMA ligands are not generally available yet.
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Psa rising whilst having chemotherapy 
Can a MRI, Cat Scan or X-ray, reveal a new met? Which one is better?
Treatment plan from Sloan Kettering docs after MRI and review of PSMA -PET…$900 -copays !!! ???? 
Continue xgeva after sbrt to bone mets?
Why not start with Axumin scan...
