Hi Debbie, there isn't really anyone that can share their experience with you as your OH has had such a rare treatment plan. As you already know, chemo was in the past reserved for men in the final stages of PCa but has more recently been used 'early' for men who are incurable as it has been shown that it can make the hormone treatment more effective for a longer time. Apparently neither of those circumstances apply to you.
NICE has not approved the use of chemo in conjunction with curative treatments so there will be very few men in the same situation as you, and those that exist will probably be at a similar stage I.e there won't be much data at the minute on what is likely to happen next.
If we take the chemo out of the picture completely (and see it simply as a bonus prize) then your closest comparison would be anyone else that has had RT/brachytherapy/HT combo, of which there are quite a few members here. Usually, the PSA is monitored for the agreed amount of time (in your case 12 months) and as long as it has stayed low and steady, the hormones will be stopped and they carry on monitoring the PSA 3 monthly to see how quickly it rises. It will rise without hormones but that is okay to a certain level because he still has a prostate. Different oncologists have different thresholds for deciding that RT/HT has failed - some say 2 or 4 or 10 and one hospital that has been mentioned on here waits until the PSA reaches 20. Ideally, an onco will monitor rising PSA with scans and any indicators of increasing symptoms rather than just the bald number. What happens then? More HT.
Quite what difference the chemo makes, I am not sure but I suspect no difference as far as what to expect next.