Multifocal high-grade prostatic intraepithelial neoplasia is still a significant risk factor for adencarcinoma

Abstract

We read with great interest the recent CUA guidelines on prostate biopsy methodology.1 We note that the recommendation regarding high-grade prostatic intra-epithelial neoplasia (HGPIN) states that “in the current era of extended biopsy schemes, HGPIN is no longer considered a strict indication for repeat biopsy and patients should be followed clinically.”1 Our Canadian research group, set out to specifically address the issue of HGPIN on prostatic needle biopsy (PNB) after 2 large review articles authored by high profile urological pathologists, rendered differing conclusions regarding the significance of HGPIN on PNB.2,3 We used a large Canadian database containing over 12 000 patients undergoing initial PNB and concluded that HGPIN, when multifocal, is a significant risk factor for prostate cancer (PCa) carrying an odds ratio (OR) of 1.38.4 In fact, the risk generally increases with the extent of HGPIN such that increasing cores involved correlates with increasing risk of PCa on follow-up PNB.4 Our initial study, although well-controlled with a benign group and statistically sound, did contain a mixture of prostate sampling protocols, so we recently repeated the study, specifically limiting the analysis to include only extended biopsy protocols yielding 10 or more cores.5 On the repeat study, we again found the same results. Patients with multifocal HGPIN carry a significantly increased risk of detecting PCa on follow-up PNB compared to patients with benign findings on initial PNB.5 Again, there is a general elevation in risk with increasing volume of HGPIN in the initial sample with 1 core showing no increased risk of PCa (OR 0.68) but 2 cores and >2 cores involved by HGPIN showing ORs of 2.57 and 3.61, respectively.5 Our studies show that HGPIN, when multifocal, is still a significant independent risk factor for PCa, even in the current era of extended PNB protocols. While it is a sound recommendation that patients with unifocal HGPIN be followed clinically with PSA and DRE, it is our recommendation and practice that patients with multifocal HGPIN should undergo a repeat biopsy within 1 year even in the absence of PSA or DRE changes. We also suggest that pathologists with expertise in urological pathology be involved in the CUA guideline development and review process, especially when recommendations are being rendered for entities diagnosed solely on the basis of morphological findings.