5 aRIs and PCa and recurrence.

[LowT]

I’m recurrent in prostate bed with three negative PSMA PET scans and essentially unchanged size of enhancing nodule over 18 months on three MRIs

DUT and FIN began when PSA reached 0.36. In six weeks dropped to 0.26 after beginning DUT and FIN.

they are affecting sensitivity of the PSMA scans.

After RO consult I decided to stop both and will rescan in two months to see if nodule becomes avid and if there are other areas as well.

If things otherwise remain unchanged may go for nodule bx to confirm and make decision to proceed with RT which planning would be greatly impacted if other sites are revealed.

As was explained to me, 5 aRIs are kind of like a mini ADT so could be masking a more aggressive cancer. So this might help in determining that.

3 ROs are willing to treat now but are also OK with this approach. There seems in a general sense in cases like mine it’s not clear, but if my PSA reaches 0.5 or greater data indicates there is a window between 0.5 & 0.8 of benefit with RT regarding development of metastasis. Waiting beyond 0.8 or 1 those such benefits are greatly diminished.

Comments appreciated.

[Tall_Allen]

"DUT and FIN began when PSA reached 0.36. In six weeks dropped to 0.26 after beginning DUT and FIN."

5aris are indicated for BPH because they shrink the prostate. You had a prostatectomy, so why were you taking them? PSMA expression is very dependent on PSA expression, so you prevented the PET scan from being useful.

"but if my PSA reaches 0.5 or greater data indicates there is a window between 0.5 & 0.8 of benefit with RT regarding development of metastasis." It depends what you mean by the word "benefit."

In contrast to a previous trial (RTOG 9601) that told us that ADT can be safely avoided if PSA<0.7, SPPORT suggests at least 4 months of ADT and whole pelvic treatment. The reason for the difference in recommendations is due to the choice of endpoint. SPPORT is telling us that if we are willing to put up with 4 months of ADT and some extra short-term toxicity from the wider field of radiation, a cure is likely. RTOG 9601 tells us that if your PSA<0.7, you aren't likely to die if you don't get the extra short-term hormone therapy, but you may have to have lifelong ADT eventually. It will always be a managed disease. Patients should acknowledge these trade-offs and discuss with their doctors.

[LowT in reply to Tall_Allen]

First 2 PSMA scans were neg while not on DUT.

At 83 and if life expectation was less than 5 years I’d probably do nothing However uncles and grandparents lived into late 80s, early 90s. One grandmother to 96.

Other considerations are lymph edema from eLND #24, osteoporosis femoral necks and nodule abutting rectal wall

[NanoMRI]

I vary imaging modalities for comparison and use blood biopsies. And as I share, I chose to reduce tumor burden with salvage pelvic lymph node surgery using frozen section pathology method. All the best!

[FlyJ]

researchgate.net/publicatio...

This article seems to indicate that several medications including dustasteride would increase PSMA expression not decrease it.

[janebob99 in reply to FlyJ]

Important results. Thank you for posting it!

[Justfor_ in reply to FlyJ]

By the quoted paper, they treated for 7 days. It is well known that, for at least Enzalutamide, PSMA expression is boosted during a period of approx 2 to 4 weeks after initialisation. After this initial boosting period there is no consensus between return to the untreated levels or bellow them. I have read some opinions stating that prolonged taking of antiandrogen drugs, finally, lower PSMA expression.

[LowT in reply to FlyJ]

I note study was in vitro and published six years ago.

[janebob99]

Dutasteride reduces PSA by reducing the volume (size) of the tumor. This has been confirmed by Moore et al. (2017) using MRI scans to measure changes in tumor size comparing dutasteride to placebo. After 6 months, men taking dutasteride had their tumors shrink by an average of 31%, while the men on placebo had their tumor size increase by 17%.

pubmed.ncbi.nlm.nih.gov/278...

This is a real effect, not a "masking" of some property.

Tumor shrinkage on Dutasteride