PSA increase following biopsy

Hi,
My PSA level was rising slowly over the last few years. I finally had a biopsy at the beginning of May this year and was diagnosed with PC. My urologist recommended AS.

In preparation for a follow up appointment, I had a PSA test last week and my PSA level had almost doubled to over 15. I read that biopsies can sometimes raise the PSA level, but I don't think it would affect it this far out?