Thanks so much everyone for these replies. I'm really pleased I joined the forum.
I had a meeting with my consultant yesterday. He is recommending TURP as I do go into retention sometimes, particularly after drinking a lot in a short space of time (e.g. a evening out). The middle lobe / "ball valve" seems to be the problem there. When I get home I self-cath and it's fine so that is buying me time to think. Most of the time I'm OK. Also my cancer is currently low risk and so RP seems too drastic (he agreed). But yes, I see the logic of killing two birds with one stone. "In context with our study, men with MLE and prostate cancer may be ideal candidates for RP in that both the cancer and urinary problems can be treated with one procedure."
https://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC3866055&blobtype=pdf
I've read that RP is more challenging after TURP and has poorer outcomes but the consultant said still achieves removal of cancer.
"good chance RP is going to be needed at some point anyway" is the crucial question. Do I improve my life now with a TURP and hope the cancer doesn't progress or go for the drastic but certain option?
I guess sit tight, watch the PSA and keep cathing to protect kidneys etc. It's all so complicated isn't it?