Is high grade prostatic intraepithelial neoplasia still a risk factor for adenocarcinoma in the era of extended biopsy sampling?

Aims: There is controversy regarding the role of high grade prostatic intraepithelial neoplasia (HGPIN) on prostatic needle biopsy (PNB) as a risk factor for prostatic adenocarcinoma. We utilise a large Canadian database to determine whether HGPIN detected on extended PNB is a significant risk factor for prostatic adenocarcinoma. Methods: Pathological findings from PNBs from 12 304 men who underwent initial PNB during an 8 year period were analysed. Patients were included in the study if their initial diagnosis was HGPIN alone or a benign diagnosis, if at least one follow-up PNB was performed, and if both the initial and follow-up PNB contained at least 10 prostate cores. Results: In the benign group of 105 patients and the HGPIN group of 120 patients, 14.1% and 20.8% were diagnosed with prostatic adenocarcinoma, respectively. When the HGPIN group was further subdivided into unifocal (1 core) and multifocal (≥2 cores) groups, 9.4% and 29.9% developed prostatic adenocarcinoma, respectively (p<0.0001). Cox regression analysis adjusting for age and prostate specific antigen (PSA) confirms the significance of HGPIN as a risk factor for prostatic adenocarcinoma (p=0.0045). Conclusions: Patients with an initial diagnosis of multifocal HGPIN on extended PNB are at a greater risk for subsequent prostatic adenocarcinoma than those with unifocal HGPIN or benign diagnoses.