That is absolutely brilliant news that your surgeon took the HIFU suggestion seriously, Roger! It must be a massive weight off your shoulders to have a more localized, less invasive option on the table instead of leaping straight into a highly complex salvage prostatectomy.
Barry and francij1 definitely gave you some golden advice there. Keeping the treatment focal with something like HIFU or cryotherapy makes an immense difference in preserving your quality of life, especially since shielding yourself from permanent incontinence is a major priority.
Getting the MRI and targeted biopsy knocked out next is the perfect game plan. It will map out the exact coordinates of those remaining localized cells so the team can see if the tumor margins are a clean match for focal ablation.
Take it one step at a time, mate. You successfully advocated for yourself and completely shifted the trajectory of your treatment plan—that's a huge win in itself. Wishing you the absolute best of luck with the upcoming scans, and please do keep us posted on how the biopsy results turn out!