How high must the PSA levels be before cancer can be seen in a CT scan?

[Mascouche]

Following the end of my treatment (radiation, lupron, Zytiga, prednisone) with curative intent back in May, my PSA has risen from undetectable to 0.09. As discussed on another thread this is not alarming at this stage since I still have a prostate as I never had surgery to remove it.

However I am questioning the wisdom of my oncologist who scheduled me for a CT scan and for a bone scan later this month as I already had those scans back in May. I don't want more radiation from scans unless it is warranted as that could always induce new cancers.

So I am wondering if someone here knows at what point do those "prostate/tumors" start to show on CT scans? If with a PSA of 0.09 they would not show, then I might as well cancel those scans until such a time that my PSA level is high enough to warrant them.

[Tall_Allen]

I don't know of any point to a bone scan/CT now. In fact, I don't know of any point unless your PSA reaches 2.0, and then it would be an mpMRI+PSMA PET/CT.

[Mascouche in reply to Tall_Allen]

Thanks

[garyjp9 in reply to Tall_Allen]

What is an mpMRI, thanks?

[Tall_Allen in reply to garyjp9]

multiparametric MRI - it's used to find areas in the prostate to biopsy.

[garyjp9 in reply to Tall_Allen]

thanks

[OzzieJ]

I just finished radiotherapy 2 months ago and my PSA is <0.03. Am now on ADT and Apalutamide. At my last monthly check they did a CT scan and bone scan. I understood it to be a baseline scan so that if something crops up in the future they can check against it. Nothing showed up on them as expected so maybe as TA suggests there is not much point.

[Mascouche in reply to OzzieJ]

I agree. To me, the scans from last May are my baseline but I do not plan on having other scans just to compare them to my baseline until there is a reason to do so (new symptoms, PSA rising to abnormal levels, etc..). I already feel like I've had enough radiation for a lifetime.

[treedown in reply to Mascouche]

I think your correct in your thinking and it is how my MO is proceeding. However for me its after hitting PSA 2.0 getting negative bone/ct but a hit in PSMA. I am sure new scans will be necessary soon enough but feel good and am very active no so doesn't seem to be much reason for it unless change is symptoms or PSA as you say.

[MiaAmia]

Whereabouts in Canada are you? We’re in Ontario. SoC here says you’ll need to have a CT and bone scan again before a PSMA CT.

Don’t hold your breath, though. Unless triaged into an emergency scan, you’ll be waiting awhile anyway. 🙁

[Mascouche in reply to MiaAmia]

I am in QC. I believe our SoC is the same as yours.

[MiaAmia in reply to Mascouche]

SoC is generally the same across Canada but then provincial funding comes into play, and QC often does its own thing. I would check with your MO to find out the regulations before they can put through for provincially funded scans. If you have the funds, your province has more private alternatives so you might be able to skip to the PSMA scan by paying out of pocket - I don't support private healthcare but we do what we have to do sometimes.

Good luck!

[NecessarilySo]

I'm not a doctor but my understanding is that scans cannot detect tumors smaller than 5mm. I once took a 4 year vacation from ADT, during which my PSA rose into the 30's. At that point I had a PET/CT scan which showed possible but questionable metastases. So, based oon my own experience, I would not take scans unless there were pain or PSA above 10, maybe 20. However, I would recognize that everyone is different and it's best to err on the safe side.

[dac500 in reply to NecessarilySo]

There is no set formula for cutoff PSA for CT scan. Take my case, I have been on intermittent Lupron for nearly 5 years. Until last year my Lupron took my PSA down to undetectable very quickly. Since then my PSA did not go down even with Lupron. As a matter of fact it has been rising slowly hovering around 0.3. My MO ordered a PSMA scan, which I will get on November 1.

[samill]

healthunlocked.com/advanced...

[Cooolone]

It all depends... PSA velocity or doubling time post therapy is what's important, not necessarily that PSA is present, let alone as noted, the Prostate is left behind.

And yes, the question is certainly what medical necessity would present the requirement for a scan? To what end or benefit would YOU have by taking the scan?

Those with an aggressive PSA velocity may benefit from early scans, and those who are low PSA or PSMA producers as well as this aligns with aggressive PCa too. But 'just because' isn't a reason. I would discuss with your team the Why's and then What's... Because as noted too, at such low PSA there's going to be very little activity or targets presenting themselves.

Disclaimer:. I've had scans below 2.0ng, and even lower, but my PSADT when recurrent was always aggressive <3 months DT. So there's that...

Everyone is different! Don't worry about what anyone else has done, talk to your team and see what they provide you as a reason for the scan. Lastly, I was always worried about too many scans and radiation, etc., etc. But again, weighing the benefit of finding what was causing my recurrence outweighed possible latent secondary issues from absorbed radiation... To each their own! I've had quite a bit of Radiation, Contrast Agents, etc., you would think I could just show up and use the machine any more without any more contrast and it'll work! Hahahahaha (joking)!

Best Regards & Good Luck

[Seasid in reply to Cooolone]

Good fun.

[tsim]

Pointless. If your PSA goes up a bit more then 3TMR and PSMAPET

[j-o-h-n]

As I've said before............. I get so many scans I'm starting to speak Scandinavian..

Good Luck, Good Health and Good Humor.

j-o-h-n Friday 09/08/2023 4:14 PM DST

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

[ron_bucher]

I don't know but "Gleason 8 Stage 4 T3-N2-M1" at your age might be a good reason to keep tabs on your cancer pretty frequently. Virtually every treatment works better the sooner it is provided.