Some way into this journey now, and the latest news is mixed.
On the positive side, my PSA levels have reduced markedly - down from 20 when first tested to just 1.2. Zoladex is clearly having a beneficial effect, so I can put up with the sweats and slight weight gain.
On the negative side, a PET/CT scan showed that there were cancerous cells in some lymph nodes and possibly in a site on one rib (this latter is still unclear - the bright spot showing up on the scan could have a different explanation). This is a worse situation than had been originally advised in the consultation with the urologist (when the cancer was believed to be contained within the prostate).
Having digested the new information, I suspect that the spread outside of the prostate had already happened before treatment started, but it wasn't identifiable through the MRI scan. It does appear that the treatment I have been receiving - Zoladex - is having a positive effect. I am still on a curative treatment path, but that may change if the site on the rib does turn out to be cancer.
In response to the revised diagnosis, I am being prescribed an additional course of anti-hormonal tablets - Enzalutamide(?) - which should start in the next couple of weeks. I have been warned that this is likely to amplify the side effects of Zoladex (any advice or observations from people who have been on a similar treatment path are welcome). The step after that is still expected to be radiotherapy, but that won't happen until late spring or early summer 2023. There will be further scans and PSA tests between now and then.
So, the news is a bit disappointing on balance, but not completely unexpected. I still feel well, and I remain positive about my prospects going forward. I think this new diagnosis will reinvigorate my exercise regime, so the recently purchased electric bike (great fun - what hills?) should see plenty of use.