PURPOSE: Prostatic intraepithelial neoplasia (PIN) is considered as a precursor lesion for adenocarcinoma of the prostate. Most data supporting this relationship comes from the short-term follow-up of patients with repeated biopsies. We report a study in which patients were followed-up for 11 years to assess the relationships between the presence of high grade PIN, low grade PIN, and atypical adenomatous hyperplasia (AAH) and the subsequent occurrence of prostate cancer.
MATERIALS AND METHODS: For 601 men treated by TURP in 1990-1993, prostate specimens were reviewed to assess the presence of high grade PIN, low grade PIN, and AAH. Incidental carcinoma was observed in 67 men. Follow-up of the 534 men without incidental prostate cancer was conducted until December 2003 and 24 new prostate cancers were diagnosed. Multivariate regression models were used to assess the relationships between PIN and AAH and prostate cancer on both cross-sectional and prospective data.
RESULTS: High grade PIN (odds ratio (OR) = 6.16, 95% confidence interval (CI): 3.28-11.58), low grade PIN (OR = 3.06, 95% CI: 1.45-6.46), and AAH (OR = 2.06, 95% CI: 1.00-4.29) were significantly associated with incidental prostate cancer. In the prospective study, only high grade PIN was associated with a statistically significant increased risk of prostate cancer: hazard ratio = 3.12, 95% CI: 1.15-8.49.
CONCLUSION: Although high grade PIN, low grade PIN, and AAH were all associated with incidental prostate cancer, the long-term prospective study showed that only high grade PIN was a significant determinant of the subsequent occurrence of prostate cancer.