Comparative Analysis of Repeat Biopsies in Patients with Isolated High-grade Prostatic Intraepithelial Neoplasia in Their First Prostate Needle Biopsies of 6 Versus 12 Cores and Systematic Literature Review

OBJECTIVE The objective of the study was to investigate the relationship between histopathological features of isolated high-grade prostatic intraepithelial neoplasia (HGPIN) and carcinoma risk in repeat prostate needle biopsies of 6 versus 12 cores. METHODS Of 114 isolated HGPIN cases were included; 64 with 6 (1st group) and 50 with 12 cores (2nd group). The number of cores with HGPIN, laterality, structural PIN subtypes, prominent nucleolus, and nuclear pleomorphism was examined in the first and follow-up biopsies. The relationship between the results of follow-up biopsies and clinicopathological findings was evaluated statistically. Furthermore, a systematic literature review was carried out. RESULTS Carcinoma was found in repeat biopsies in 15.6% of the cases in 6-core and 24% of cases with 12-core biopsies (p=0.006). Carcinoma detection rate was significantly higher in cases with >= 2 cores with HGPIN than in cases with a single core of HGPIN (p=0.007). The rates of carcinoma and persistent HGPIN were higher in multifocal and bilateral HGPIN cases, compared to unifocal, or multifocal but unilateral cases (p=0.018). In both groups, prominent nuclear pleomorphism was significantly more common in cases with carcinoma (p=0.023). The systematic literature review revealed 25.6% of carcinoma risk out of 5580 isolated HGPIN patients. CONCLUSION Carcinoma detection rate in repeat biopsies of 12-cores was significantly higher than cases with 6-core biopsies. The HGPIN cases with >= 2 cores, bilaterality, and presence of prominent nuclear pleomorphism were found to be significant histopathological markers in predicting patients with carcinoma. Close follow-up of high risk patients with repeat biopsies in addition to clinical parameters was recommended.