Objectives: The natural history of high grade prostatic intraepithelial neoplasia (HGPIN) is incompletely understood limiting evidence based recommendations regarding screening and repeat biopsy intervals. Our objective was to evaluate the natural history of HGPIN to better assess the time frame to disease progression and the pathological findings at the time of progression to cancer.
Methods and materials: We retrospectively reviewed 74 consecutive patients with an initial diagnosis of HGPIN. The number and timing of all biopsies leading to the diagnosis of cancer were assessed. Clinical and pathological features of those patients with eventual disease progression were evaluated.
Results: The mean number of biopsies performed before subsequent cancer diagnosis was 5 (range: 3-13). The mean time to the diagnosis of cancer was 29 months (range: 7-83). Men with a history of HGPIN had lower percent positive biopsies at the time of cancer diagnosis (p < 0.001) and smaller volume tumors on final pathology (p = 0.041) compared to men without a history of HGPIN.
Conclusions: Patients with an initial diagnosis of HGPIN on transrectal ultrasound (TRUS) guided biopsy progressed to cancer at a mean of 29 months. The vast majority of patients that progressed to prostate cancer had low volume disease at the time of diagnosis and definitive treatment. Our data indicate the importance of re-evaluation in HGPIN patients and suggest a trend toward low volume disease in carefully followed patients. Prospective data is warranted to adequately define an evidence based biopsy regimen in men with HGPIN.