Purpose: Repeat biopsy has been advocated following the diagnosis of high grade prostatic intraepithelial neoplasia to exclude coexisting prostate cancer. We further define the natural history of high grade prostatic intraepithelial neoplasia by determining the incidence of prostate cancer 3 years following diagnosis.
Materials and methods: A total of 31 men underwent followup interval biopsy 3 years after high grade prostatic intraepithelial neoplasia diagnosis in 1996 to 1997, regardless of change in serum prostate specific antigen (PSA) or digital rectal examination findings. A single pathologist reviewed all biopsy specimens. All men had a minimum of 12 biopsy cores taken at the time of diagnosis.
Results: A 3-year followup interval biopsy eight (25.8%) men had prostate cancer, 11 (35.5%) had high grade prostatic intraepithelial neoplasia only and 12 (38.7%) had no disease. Mean serum PSA at diagnosis and before the followup biopsy was 6.88 and 9.69 ng./dl., respectively (p = 0.008). Of the men 48% had less than a 1.0 unit increase in serum PSA. Upon univariate regression analysis change in serum PSA was not associated with the detection of prostate cancer (p >0.10). All 4 patients who subsequently underwent radical prostatectomy had organ confined disease.
Conclusions: In a high proportion of men with high grade prostatic intraepithelial neoplasia prostate cancer will develop in a 3-year interval. Our findings support the concept that high grade prostatic intraepithelial neoplasia is a precursor to prostate cancer and that repeat biopsy at a delayed interval is recommended regardless of changes in PSA.