Clinical evolution of prostatic intraepithelial neoplasia.

High-grade prostatic intraepithelial neoplasia (PIN) is most likely a precursor of prostate cancer and is frequently associated with it whereas the direct link between low-grade PIN and cancer is not established. The clinical evolution of isolated high-grade PIN has been the object of much concern because of the possibility of undiagnosed prostate cancer or the evolution of this premalignant lesion in invasive carcinoma. Parameters predictive of the later finding of prostate cancer on repeat biopsy in patients with PIN are of evident interest and we have reviewed our experience and recent data from the literature on this topic as well as on the clinical management of these patients. Low-grade PIN is not by itself a risk of later cancer found on repeat biopsy unless other factors such as PSA increase the cancer suspicion. Patients with low-grade PIN and high serum PSA should therefore undergo repeat biopsies. Patients with low-grade PIN and without additional factors should be followed. Patients with high-grade PIN should systematically be rebiopsied. If a second set is still consistent with PIN, they should undergo additional biopsies again within 3-6 months because they are likely to have an undiagnosed cancer.