SBRT & PSA Reading

[tallguy86]

Received 5 TX of SBRT in July. (GS 6-T1c-6 cores) PSA at start of TX was 11.90. PSA on Sept 1st was 7.55. Will see urologist in 4 months. He said ultimately .05 PSA would be the ideal value. Could someone please explain Pc treatment and post PSA values. Trying to wrap my head around this to have a better understanding. Thanks much!

[Tall_Allen]

I think you got the decimal in the wrong place. Ideally, PSA will eventually get below 0.5 ng/ml. But it may take several years to reach the low point (nadir) with several bounces along the way.

Radiation kills cancer cells by inserting a free radical into the DNA. Cancer cells can't repair that damage, so when they try to divide (which can be several years - they go into hibernation) they die. Healthy prostate cells can repair the damage, so they continue to thrive and produce some PSA.

[tallguy86 in reply to Tall_Allen]

Thank you. That makes sense! I was curious why it required so much time for the PSA to trend downwards.