Spike in PSA number

Oh my, where to begin?? In ‘06 I was diagnosed with Pca. With a PSA score of 28, I was told I needed to get checked pronto. Biopsy showed 6/12 positive with a Gleason score of 8. After the battery of scans, x-rays and such. It was time to determine best course of treatment. Being that the cancer had escaped the capsule, and feeling that neither surgery for the prostate removal nor radiation treatments had a significant advantage over either one, I elected to go with 46 radiation treatments and shots of Eligard every 6 months plus daily dosage of 25 mg Casodex. For the past 17 years, I’ve been at .4 to undetectable on this regime.
This past fall, I began to have increased numbers of kidney stones. (I’ve had them for 60 years.) Suffering with these things every 4-6 weeks! The pain meds prescribed constipate me terribly. I read on the internet that constipation can cause PSA numbers to spike but could this happen if my prostate had been eradicated? My PSA numbers went from .468 to 1.810 in 4 months!?!
Has anyone in the group experienced something like this? I’m scheduled for a pet scan in 2 days. My urologist is leaning towards a reoccurrence. To say my deflated is an understatement .
Any info would be appreciated.
Have a great week.