PSA result in-what does it mean?

There is nothing you would do differently if that is your nadir or isn't - only time will tell.

If you round off the last decimal, your last two PSAs were 0.8 and 0.9. I'm not the expert here, but I'm not sure that's a significant difference.

noise, if you still have a prostate, the levels can vary as the prostate will create some PSA, Also the difference between .3 and .4 isn't that large in terms of PSA. In this case nadir would be .3 (the lowest point). BCR would then be 2.3, so there's a low of room for bouncing, noise, and other points of anxiety before any further treatment would be recommended.

If a future test reported a PSA of .2, nadir would then become .2.

Andrew

I remember some men reporting that it took them 5 years to reach nadir after radiation.

I agree that the fluctuations are very small and probably currently insignificant as far as the PCa goes. After radiation you want two main trends. First, a reduction in the PSA, which you have seen; and then stability within a range less than the amount that would signify recurrence. Along the way many experience the bounce, as it appears you have, and some experience a rise before becoming stable. So for you it would be long term stability below 2.75. I have read that a great target nadir is .50 or less, but that doesn't mean that a nadir of .75 isn't just as good.

Based on PSA expression estimates made by Dr. Steven Strum several years ago, healthy benign prostatic tissue express PSA at an average rate of .066 per cc of volume. So a PSA of .85 would indicate volume of about 12.88 cc. Normal volume in men of prime PCa age is in the 30-40 cc range.
Radiation often affects the PSA expression of the remaining prostatic tissue. Many men will have positive PSA after radiation, but some become and remain undetectable. It is really very individualistic.

You continue to watch the PSA as you are, but you shouldn't get alarmed unless it continues a rise to and over the nadir plus 2. If you start getting close, then more investigation would be in order. If you continue to increase by a factor of .09 per quarter it will take about 6 years to reach the nadir plus 2 benchmark. If the rise continues and increases more rapidly, then I would be doing more investigation. I would talk to the RO and get advice as to what to look for and what the next steps would be.

There is a difference between the nadir so far, and the nadir with hindsight. All we know as we go along is the nadir so far. Hindsight is only available on longterm retrospective studies.

"Who knows" Is exactly the point. You've got numbers you don't like and are not heading the right way.

Sadly you're stuck in that horrible, "keep monitoring" stage. Until the numbers show a consistent pattern - well there's nothing to do but wait and retest in a few months. That's an awful place to be.

Uncertainty is the most emotionally difficult thing to face with this thing. You don't have enough info to act or relax as the sword is still hanging.

I wish there was more I could say, but "hang in there and retest in a few months" is the best I have today.