Quantification of perineural invasion focus after radical prostatectomy could improve predictive power of recurrence.

Perineural invasion (PNI) after radical prostatectomy (RP) is a common feature of prostate cancer (PCa) and has been associated with unfavorable tumor characteristics. However, its prognostic relevance is controversial. In this study, we evaluated the impact of both PNI status (PNI+ vs PNI-) and quantified number of PNI focus on the long-term prognosis of biochemical recurrence (BCR) after RP.

After reevaluating PNI of a total of 721 patients with localized PCa who underwent RP at our institution between 2000 and 2002, we examined associations between PNI status or PNI focus number and clinicopathological factors including tumor stage, Gleason score (GS), margin status, tumor location, preoperative prostate specific antigen, age, prostate weight as well as BCR outcome.

PNI was present in 530 of 721 cases (73.5%) of the RP specimens and was associated with more aggressive disease. BCR occurred in 19.4% of all patients within a median follow-up period of 8.5 years. PNI+ status was associated with poor BCR prognosis in univariate analysis but lost in multivariate analysis. Based on the number of PNI focus, PNI were further divided into two distinct group: PNI+a (≤3) and PNI+b (>3). In a multivariate Cox regression model, PNI+b (>3) was identified as an independent BCR prognostic factor.

Quantification of PNI focus number beside the dichotomized status recording will not only provide more detailed information but also be a novel prognostic indicator for risk stratification. Further external validation will be needed for an optimal cut-off value of the PNI focus number. Our findings will help further research on the relevance of PNI in the pre-treatment setting and support ongoing efforts to understand its role of cancer progression.

Human pathology. 2020 Jul 13 [Epub ahead of print]

Shulin Wu, Ling Xie, Sharron X Lin, Gregory J Wirth, Min Lu, Yifen Zhang, Michael L Blute, Douglas M Dahl, Chin-Lee Wu

Department of Urology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts., Department of Pathology, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China., Department of Urology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts., Division of Urology, Department of Surgery, Geneva University Hospital, Geneva, Switzerland., Department of Pathology, Peking University Third Hospital, Peking University Health Science Center, Beijing, China., Department of Urology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts. Electronic address: ., Department of Urology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts. Electronic address: .