Sudden drop in PSA in just one month

I'm just a laymen on this forum, but my understanding is that cancer cells are just like other cells, they are on a quest to live and divide and keep on going. PSA is something that is expressed by the prostate cancer cells. Maybe something changed in your diet or overall existence such that the prostate cancer cells are not as lively as other months, and as a result they gave off a bit less PSA.

There might be a glitch even with the same lab. A retest might be in order

@sam60 What treatments are you getting? Your PSA is very low unless your had surgery.

My radiologist/oncologist state if you have a prostrate you will have PSA. It is the rising numbers that are concerning to doctors. Mine rose steadily for several years until my diagnosis and treatment.

If you have a prostrate your PSA will go up and down and many things can affect it going up like bike riding, irritation, infections, etc.

Harvey. Thanks for your response. I’m a Harvey too and hoping to remain so for a long long time

No prostate removed 6 years ago and 38 radiation treatments. One year later it metastasized to my hip more radiation . PSA back to undetectable for5 years. Then slow rise to .9 and then I one month down to .4 ?

I had a PSA of 5.7 and my PCP said to repeat it in 6 months. I did and it was down in the 2's. I felt such a sense of relief but also I started to question why such a large change in such a short time, 6 months. I then recalled that I had a herniated disc that was very, very painful and I was prescribed 6 days of Prednisone to help with the inflammation. My 6 month blood draw was a week after I finished the steroid. I mentioned this to the urologist I followed up with and he said he did not think that was the cause so almost a year after the 5.7 PSA I had another lab done and it was 7.7! He asked if I wanted a biopsy. I said yes, but only after a prostate MRI that then showed a PIRADS 4. I waited a few days and he never called with the results, so I started looking for a urologist who only did oncology and I had my biopsy which was positive and then 18 months of ADT therapy and 39 proton beam treatments. My last PSA last week was a 0.01, that's 17 months after completion of the proton radiation and 8 months after the last 6 month Eligard injection. The Eligard is still in force because my testosterone was 16 and I feel that is the reason my PSA was only 0.01 and after it finally wears off I expect my PSA to increase some, but remain below the threshold for having had radiation treatment.

Given that you have CRMPC, I would retest PSA and discuss with your oncologist the benefit of a PSMA PET scan. Unusual PSA results for CRMPC patients often benefit from a PSMA PET scan, to ensure no new tumors and/or mutations that affect PSA results.

Just had a PMSA scan 2 months ago and insurance would not pay with a drop in PSA !

Assuming nothing showing on PSMA PET scan when PSA was 0.9, I too am looking forward to learning what could cause the PSA to go down to 0.43. Has your testosterone level been checked recently?

May be the rise was due to inflammation or other causes?
Dont mind me. I am just another layman trying to make some sense of the whole thing.