[759] High-Grade Prostatic Intraepithelial Neoplasia (HGPIN): Preinvasive Lesion of Adenocarcinoma (CA) or Epiphenomenon? A Topographic Study of HGPIN and CA in Radical Prostatectomies (RP).

Antonio AAV Brasil, Athanase Billis, Luciana Meirelles, Leandro LL Freitas, Paola H Poletto, Priscila Zubioli, Wagner J Favaro, Valeria HA Cagnon, Leonardo O Reis, Ubirajara Ferreira. School of Medicine, University of Campinas (Unicamp), SP, Brazil

Background: The clinical importance of recognizing HGPIN is based on its strong association with prostatic CA. It is the most important risk factor for concomitance of prostate cancer on needle biopsy specimens. HGPIN coexists with cancer in >85% of cases. In spite of this high frequency of coexistence, transitions between HGPIN and stromal invasion very rarely are seen. This fact highlights the possibility of HGPIN to be an epiphenomenon. To address this issue we studied the topographic relation of HGPIN and CA in RP.
Design: We studied the frequency of quadrants showing only HGPIN, only CA, and HGPIN+CA in a total of 3186 quadrants from 100 whole-mount consecutive surgical specimens. Extent of HGPIN and CA was evaluated by a semiquantitative point-count method previously described. Points were considered coincident whenever HGPIN or CA were seen in a distance ≤5mm; non-coincident whenever in a distance >5mm. The means were compared using the Kruskal-Wallis and the Mann-Whitney tests. For the comparison of extent we used the Spearman correlation coefficient.
Results: HGPIN was present in 80/100(80%) radical prostatectomies. The mean (range) of quadrants showing only HGPIN, only CA, and HGPIN + CA was 0.74 (0-7), 8.53 (0-29), and 1.88 (0-13), respectively (p<0.01). The mean (range) of coincident points was 0.60 (0-4) and non-coincident 2.00 (0-15) (p<0.01). There was no significant correlation between extent of HGPIN and CA (r=0.16, p=0.11). The mean (range) of anterolateral quadrants showing HGPIN was 1.31 (0-8), and of posterolateral quadrants 1.80 (0-10) (p=0.07). Unequivocal transition between HGPIN and stromal invasion was seen in only 1/100 (1%) radical prostatectomies.
Conclusions: In specimens of radical prostatectomy most of the quadrants showed only CA and not HGPIN+CA. Extent of HGPIN did not correlate with extent of CA and the foci of HGPIN were significantly located in a distance >5mm from CA comparing to foci in a distance ≤5mm. No significant difference in frequency of HGPIN was found comparing anterolateral quadrants vs posterolateral quadrants. The lack of topographical association between HGPIN and CA and the very rare transition between HGPIN and stromal invasion, seem to favor the possibility that HGPIN may be an epiphenomenon.
Category: Genitourinary (including renal tumors)

Wednesday, March 2, 2011 9:30 AM

Poster Session V # 74, Wednesday Morning

 

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