Using cutting-edge technologies including next-generation sequencing of laser capture microdissected tissue, we are comparing the mutation profile of tumor samples to cell-free DNA purified from matched plasma. We hypothesize that circulating tumor DNA levels will be a predictive biomarker for determining the choice of treatment and disease management for both active surveillance candidates and patients after radical prostatectomy. Our objective will also be to determine whether a rise in circulating tumor DNA levels predicts an increase in PSA levels.