Morphometric analysis and clinical followup of isolated prostatic intraepithelial neoplasia in needle biopsy of the prostate.

PURPOSE

We evaluate the significance of grade and extent of isolated prostatic intraepithelial neoplasia in prostate needle biopsies as a predictor of cancer on repeat biopsy.

MATERIALS AND METHODS

We reviewed our experience with 58 men 50 years or older who had isolated prostatic intraepithelial neoplasia on initial prostate needle biopsy during a prostate specific antigen (PSA) based screening trial for prostate cancer. All 58 men underwent repeat biopsy to follow the initial findings of prostatic intraepithelial neoplasia. We assessed the relationship of patient age, digital rectal examination, serum PSA concentration, PSA density, prostatic intraepithelial neoplasia grade, number of foci of neoplasia and linear extent of prostatic intraepithelial neoplasia in the initial biopsy specimen to the finding of cancer on the repeat biopsy. We also compared the cancer detection rate in the 58 men with and 427 without prostatic intraepithelial neoplasia in the same screening trial.

RESULTS

Of 21 men with low grade and 37 with high grade prostatic intraepithelial neoplasia 4 (19%) and 19 (51%), respectively, had cancer on repeat biopsy (p < 0.02), compared to 82 of 427 (19%) without cancer or prostatic intraepithelial neoplasia on the initial biopsy. High grade prostatic intraepithelial neoplasia was a significant predictor of malignancy on repeat biopsy (p < 0.05). The number of foci of neoplasia and the linear extent of prostatic intraepithelial neoplasia on initial biopsy were not predictive of cancer on repeat biopsy.

CONCLUSIONS

Our results demonstrate that the presence of high grade prostatic intraepithelial neoplasia is a strong predictor of prostate cancer in men with elevated serum PSA concentrations and they should be followed with repeat biopsy.