I am not a doctor or an expert... That said, I see with your numbers that you were a Gleason 8 which is an agressive form of PCa and maybe one of the reasons your doctor is so concerned.
If it was me, I would most likely request a high senstivity PSA test as a 0.1 could be anywhere from 0.06 to 0.14. As you can see from my numbers, I had a rise in PSA over a 3 year period and the higher senstivity test enables a better tracking of rising PSA. My Gleason was only a 6, but the fact that I had some focal margins and 3 consecutive rises in PSA, I was recommended and opted for salvage radiation (SRT) when my PSA level was 0.13 as the numbers suggested reccurence in the prostate bed and SRT was a viable treatment.
You can research more here and in the literature and seek another professional opinion, especially with the more sensitive PSA result and go from there. But with a Gleason 8, I am not sure of time constraints. Professionals know best there. I had time due to being a Gleason 6. But you certainly have time for another opinion.
I can say that the SRT treatments had little side effects for me, but they do vary greatly from patient to patient.
Sorry to hear of your results, but this dang PCa is a beast. Fortuneately, you still have treatment options to consider.
After 3-4 years of annual PSA 4-6, biopsy recommended
3/13/2007 - 12 point biopsy - Left 0/6 Right 1/6 Gleason 3+3 T1c
4/24/2007 - DaVinci performed at Virginia Mason hospital in Seattle
5/2/2007 - Catheter Out! Final pathology of Gleason 6 T2c Nx Mx, approx 20% of prostate involved, positive margin, but only at 2 focal points.
6/28/2007 9 weeks incontinance... Overnite, went from 4-6 soaked pads a day from prev 8 weeks to 2 barely wet pads a day.
7/12/2007 11 weeks post-op Minimal leakage... one small pad a day
7/18/2007 First Post-Op PSA... 0.01 !!!
9/10/2007 Pad free and ED at 75% with 100mg Viagra generic
6/26/2008 2nd Post-OP PSA at 14 months... 0.02
12/2/2008 3rd Post-OP PSA at 20 months... 0.03
10/30/2009 4th Post-OP PSA at 31 months... 0.13 (moved and diff lab)
11/3/2009 Retest at my original lab... 0.11 (followup with Doc sched 11/10)
11/10/2009 Discussion indicated biochemical reccurrence and need for salvage radiation treatment.
1/21/2010 Another PSA test at 34 months... 0.14
1/26/2010 IMRT Salvage Radiation Treatment started
32 sessions for 64 gys total.
3/12/2010 Finished 32 sessions... No side effects to date except a little
tiredness. Slight changes in bowel movements the last week...
4/8/2010 Pretty much all side effects (were minimal) are gone now and energy has returned. Now just wait for the upcoming PSA test.