Okay - NICE says that biochemical recurrence in a man with no prostate is a PSA of 0.2 - or a PSA with 3 successive rises over 0.1
The unreliability of ultra-sensitive testing is now better understood and some top cancer hospitals have stopped offering them, offering PSA results only to 1 decimal point. The machines are calibrated regularly but it isn't only prostate cells that produce PSA, it also comes from the adrenal gland and other parts of the body. Women have an average PSA of 0.005 which can rise as high as 0.02 after orgasm and higher in breast milk.
Our urologist told me that if you took one blood sample and tested it in the exact same machine a number of times, the result could be anything from 0.01 - 0.05. In reality, most labs have more than one testing equipment anyway so the test from 3 months ago isn't necessarily from exactly the same machine, or the machine could have been recalibrated in between times. Or you could have been cycling or masturbated just before the second or third test, or have done something that stimulated your adrenal gland (been late for the appointment/found it hard to park/had a row with the boss/had to get a big piece of work completed?). We actually tested it with my dad - he had one blood sample tested twice on the same day and got 2 diffrent PSA results.
Your body may simply be settling into its new normal in terms of PSA production. My husband has no prostate but his new 'normal' hovers between 0.09 and 0.11 - he does do a lot of weights and also gets very stressed about some things so it might be down to that?
Looks at Franc's profile - that may reassure you a bit https://community.prostatecanceruk.org/default.aspx?g=profile&u=21040
It is important to listen to the onco of course but I would be very unhappy if a member of my family was told to have salvage RT/HT based on these tiny numbers. The exception would be if your medics already knew from the pathology that you had a positive margin, seminal vesicle invasion or lymph nodes affected.