Initial Prostate Health Index (phi) and phi density predicts future risk of clinically significant prostate cancer in men with initial negative prostate biopsy: a 6-year follow-up study.

Initial phi or phi density predicted 6-year risk of PCa in men with initial negative prostate biopsy. Men with higher phi (≥35) or phi density (≥1.2) need closer follow-up and repeated investigation, while men with lower phi (<25) or phi density (<0.4) could have less frequent follow-up.