PSMA PET / COMBIDEX MRI

[SoonerMark]

Hoping to find some help with scans. What is the difference between PSMA PET and Combidex MRI. I think the Combidex mainly targets lymph nodes but want to know if both are full body / all organ / bone. Are both scans independent or would a single PSMA cover everything ? Finally, will an artificial urinary sphincter with a 3 Tesla max interfere with either ?

[Tall_Allen]

This discusses Combidex MRI vs PET/CT:prostatecancer.news/2016/12...

Combidex only reveals cancerous lymph nodes, not organs or bone. It is only available at Radboud University in the Netherlands.

They are completely different kinds of scans.

The AUS may interfere with an MRI but will not interfere with a PET/CT.

[SoonerMark in reply to Tall_Allen]

Thank you Tall Allen, so happy I found this group with so much knowledge.

[Schwah in reply to Tall_Allen]

So for someone like myself, with 60% of a prostate, would a negative PSMA scan preclude the need for an MRI of the remaining prostate itself? In other words would a PSMA scan be expected to show any cancer in the remaining prostate in addition to showing any Metastasis throughout the body?

Schwah

[Tall_Allen in reply to Schwah]

In a recent study, mpMRI and PSMA PET/CT were equivalent at finding cancer in the prostate in untreated men (all the men had prostatectomies afterwards)pubmed.ncbi.nlm.nih.gov/312...

[Schwah in reply to Tall_Allen]

Perfect. Thank you

[LeeLiam in reply to Schwah]

Schwah, I had seeds and EBRT in 2006. My PSA was undetectable for years but has been rising for three years now at 3.7. I had an Axumin scan on 9/10. It showed a suspicion of cancer in the central prostate, nowhere else. Then I had a rhPSMA trial scan on 10/23. It showed nothing in the prostate but suspicion of cancer in T8 vertebrae pedicle. Totally opposite results. They said sometimes local cancer does not express much PSMA. I had an mpMRI of the prostate bed that looks negative. Then I had a whole body mpMRI last week. It is being evaluated now. It makes it hard to depend on any of these.

[tango65]

Combidex targets lymph nodes only and it is a full body scan. It has a better detection rate than PSMA PET/CTs since it can detect lesions in the nodes that are 2 mm or larger , meanwhile the PSMA PET/CTs detect lesions 4 mm or larger. If interested get in touch with:

Solange Estourgie

Management Assistant Radiology & Nuclear Medicine Department

Prostate MR Reference Center

[e-mail]

T +31 (24) – 361 91 96

PSMA PET/CTs are also whole body scans and detect lesions in organs, lymph nodes and bones. The detection rate is associated with the PSA values. It is 90 plus % with a PSA of 2 or higher and around 50 % with a PSA of 0.4 or lower. It could have false negatives when the cancer is neuroendocrine (low PSMA expression) or in regular PC after multiple treatments.

[SoonerMark in reply to tango65]

I'm new to this and have depended on my Urologist at a university cancer center for treatment and information. When I recently received my 0.21 PSA after salvage radiation, I was alarmed because what I've read indicated a second failure. I'm not under any treatment other than to return in a few months to get another PSA.

So I started looking for resources and found this group of well informed people. One day, I hope to learn and become a resource for others as so many of you have been to me.

Everything I've read indicates metastasis occurs in the bones, liver and lungs but I dont see any specific reference to lymph nodes. What is the benefit of the Combidex scan or identifying cancer in the lymph nodes vs the whole body scan of a PSMA.

If you could only have one, which would be more beneficial ?

How often should a scan be performed to stay ahead of tumor growth ? It could get quite expensive until insurance will pay.

[tango65 in reply to SoonerMark]

Good questions. I started to get PSMA PET/CTs in 2016. The first one diagnosed metastases in the lymph nodes in the pelvis and in the retroperitoneum up to the renal arteries. Cancer in lymph nodes outside pelvis are considered metastases ( M1a) Cancer in the lymph nodes inside the pelvis are not considered metastases (N1) .

cancer.org/cancer/prostate-...

The combidex scan could be useful if a PSMA PET/CT does not show cancer anywhere and the PSA is increasing. If there is PC in the lymph nodes and the tumors are less than 4 mm they would be missed by the PSMA PET/CTs. If there are lymph nodes with cancer and the tumors are 2 to 4 mm they can be detected by a Combidex scan . Once they have been detected they could be treated with SBRT if location allows it.

The scans are performed according to the evolution of the cancer. If your PSA is increasing and the PSADT is less than 10 months and/or associated with increasing ALP, a scan is indicated. I prefer to have a PSMA PET/CT because they have the higher detection rate. If it were negative one could consider a combidex scan, but these scans are done only in the Netherlands. I consulted with RO and they are willing to irradiate lymph nodes if they are positive in a combidex MRI.

[SoonerMark in reply to tango65]

In absolute numbers my PSA numbers are very low, but the trend has always been up. When I entered the results in a PSA calculator I found on a website, it was 3.5 months. After my RP, it also rose very quickly and quadrupled in about 6 months.

I think my cancer is fast growing and aggressive. My diagnostic biopsy was 3+3, but less than a year later, my pathology was 4 + 4 with 95% being a 4.

I've been considering both scans, but dont want to do it too early to be effective. Insurance doesnt cover and if I have to go out of country, there's the additional quarantine period, if you get permission to travel for medical necessity.

I'm concerned how often this will have to be done as I dont live close to a medical facility offered either type scan.

[tango65 in reply to SoonerMark]

The doctors from the TUM in Munich advised me to plan a PSMA PET/CT when the PSA was around 0.4 after my PSA started to go up.

You could get a PSMA PET/CT at UCLA or UCSF but you need to plan in advance since they are been booked after the study was approved by the FDA.

UCLA Nuclear Medicine

200 Medical Plaza, Suite B114

Los Angeles, CA 90095

PHONE: [phone]|FAX: [phone]

UCSF

Radiology Scheduling [phone] to schedule PSMA scan

There are clinical trials and you need to see if you qualify for any of them:

clinicaltrials.gov/ct2/resu...

clinicaltrials.gov/ct2/resu...

[cigafred]

I've had the Combidex scan, and then lymph node radiation. I think the answers you have received from the others here are accurate. There is a web site for the Combidex, radboudumc.nl/en/patientenz.... Professor Dr. Barentsz runs it and is great.

[SoonerMark in reply to cigafred]

Thank you for the information.

[SoonerMark in reply to cigafred]

I think they are now referring to this as Ferrotran in an effort to gain approval and export to the rest of the world. Hopefully it will get to the US soon.

[cigafred in reply to SoonerMark]

Yes, when I was there they had updated to "nano-iron," now this. Barentsz spent about an hour explaining to me why on the first try FDA approval was not obtained. The original team did not have a radiologist involved, and many other mistakes, so approval was denied, and Barentsz has a fascinating story about his quest to purchase the rights.

[j-o-h-n]

Greetings, It's a good thing you came here Sooner than Later. OK I get it..... Keep asking here for important up to date info....

Good Luck, Good Health and Good Humor.

j-o-h-n Thursday 12/03/2020 5:04 PM EST

[j-o-h-n]

Oops I forgot..... get yourself a (good) M.O. instead of your urologist......Ask here for recommendations.....

Good Luck, Good Health and Good Humor.

j-o-h-n Thursday 12/03/2020 5:10 PM EST

[SoonerMark in reply to j-o-h-n]

Thank you j-o-h-n, appreciate the advice and encouragement.