False positives

[Purple-Bike]

All is not cancer that lights up on the scans!

In February, a PSMA PET/CT found nothing abnormal, just a minimal PSMA signal from rib 10 right.

But the NaF PET/CT:

"On the right, rib 10 has abnormal PET uptake (SUVmax 27.3). The same rib uptake can be seen in previous bone scintigraphy and as a minimal bone signal on previous PSMA PET, suggesting bone metastasis. In addition, rib 8 on the left side has abnormal uptake with minimal sclerotic change on CT (SUVmax 34.9).

Other skeletal tracer signals are physiologic or due to age-related degenerative changes.

Conclusions: Rib 10 on the right and rib 8 on the left have abnormal PET uptake and CT sclerosis concordant with bone metastases. Rib 10 also had minimal PSMA uptake".

The clinic wanted me to SBRT the two suspected mets right away. Plus 7 months ADT, nothing more, although I have BRCA2+. "PARP inhibitor + abiraterone not needed and very toxic". Whack-a-mole is the philosophy and that is how the clinic makes its money.

A video consultation with a second opinion told me it was not certain it was cancer recurrence and advised me to put all treatment on wait which I did.

Three months later, at another clinic, in my home town, I had another PSMA PET/CT. It showed that the uptake was unchanged from the earlier scan and unchanged from a corresponding find in both ribs on an older CT from 2008 that I didn´t know existed.

So apparently still in remission almost four years after dx with a single met spotradiated and just ten months of ADT. My limited systemic treatment was a gamble but knock on wood until now it seems it works.

[Tall_Allen]

NaF18 PET is twice as sensitive as PSMA PET for finding bone metastases.

jnm.snmjournals.org/content...

[Purple-Bike in reply to Tall_Allen]

That is true. However, what the new PSMA PET/CT found for the two suspected rib lesions from the NaF was

- "a weakly increased PSMA-uptake with corresponding discrete densification on CT which is unchanged compared to an older CT from 2008"

respectively

- "a PSMA-negative screlotic change that is unchanged compared to an older CT from 2008".

With these two observations, surely the concerns raised by the NaF of the two suspected mets can be set aside?

[Tall_Allen in reply to Purple-Bike]

If there were no CT correlates, it probably is not metastatic. But can you explain: "sclerotic change that is unchanged compared to an older CT from 2008" It is either changed or unchanged, no?

[Tasmanian in reply to Tall_Allen]

I read that to refer to bony sclerosis being a change in itself and that it had not though altered in appearance since it was first seen.

[Purple-Bike]

Right. Combined with recent tests showing a declining cf DNA, undetectable PSA, steady ALP, and chromogranin A and neuronspecific endolase being in the reference range, the scans should be a strong indication that my cancer currently is in remission, knock on wood. No treatment needed.

I agree, that phrase is ambivalent. I refer to Tasmanian´s reading.