Only thing I could find quickly on larger prostates.https://ro-journal.biomedcentral.com/articles/10.1186/s13014-014-0241-3
Epstein 2nd opinion would let you know if the pathology is better or worse than the first opinion. Not sure what you would do with that info. If his group said it was all 3+3, would you stay on AS? If it was a little worse, would you change your treatment plan? It is only as good as the biopsy is representative of the whole prostate which is always questionable.