Clinical prognostic criteria for later diagnosis of prostate carcinoma in patients with initial isolated prostatic intraepithelial neoplasia.

Prostatic intraepithelial neoplasia (PIN) is considered as a precursor of prostate cancer and is frequently associated with it. Diagnosis of PIN on a prostate needle biopsy without associated carcinoma is a difficult problem since high-grade PIN does not necessarily mean that prostate cancer is always present and low-grade PIN is associated with cancer as well. Definition of parameters predictive of the later finding of prostate cancer on repeat biopsy in patients with PIN is of evident interest and we have reviewed our experience and recent data from the literature on this topic. High grade is a strong predictor of later cancer found on repeat biopsy (50-100%) and in these patients, serum prostate-specific antigen (PSA), digital rectal examination and transrectal ultrasound are predictors of later cancer found on repeat biopsy. High-grade PIN is, however, frequently associated with later cancer whatever PSA, even when < or = ng/ml. Low-grade PIN seems to behave like BPH since the incidence of later cancer is extremely low when PSA is < 4 ng/ml and is high when PSA > 10 ng/ml. Patients with high-grade PIN should systematically be rebiopsied after 3-6 months to exclude cancer because they are likely to have undiagnosed cancer. Patients with low-grade PIN and low PSA seem to have a low risk of later cancer found on repeat biopsy. Patients with low-grade PIN and high serum PSA should have repeat biopsies because the incidence of subsequent cancer is high and comparable to high-grade PIN. Further investigations are needed to optimize the management of patients with low-grade PIN and intermediate PSA level.