This might help I’m also PIRADS-4, clinically significant cancer likely to be present,
https://radiologyassistant.nl/abdomen/prostate/prostate-cancer-pi-rads-v2
I had a biopsy and am awaiting the results as your husband is, the only way to know more is to wait until the biopsy results are available. This will still be only an analysis of the samples they have taken and not a 100% result.