Digital versus light microscopy assessment of surgical margin status after radical prostatectomy

Positive surgical margin (PSM) extension reported as focal or non-focal/extensive is an important pathologic prognostic parameter after radical prostatectomy. Likewise, there is limited or no agreement on how to measure and what the best cut-off points to be used in practice are. We hypothesized that digital microscopy (DM) would potentially provide a more objective way to measure PSM and better define its clinical significance. To further our knowledge, we have evaluated PSM status in 107 laparoscopic radical prostatectomies using digital and conventional light microscopy (LM). DM evaluation detected three additional PSM cases, but no differences were seen (LM vs DM; p = 0.220). Mean linear measurement correlated to biochemical recurrence (BR) (LM, p = 0.002; DM, p = 0.001). ROC analysis identified a cut-off point to assess linear measurement by LM (3.5 mm) or DM (3.2 mm), but only digital measurement was significant for BR-free survival. Our study also evaluated a cut-off ≤ 3 mm that was associated to BR using LM (p = 0.023) or DM (p = 0.001). Finally, the number of paraffin blocks bearing PSM correlated with BR (p < 0.001) status with either LM or DM. In conclusion, DM produces similar data than LM but shows more accurate measurements. Reporting of PSM with score of ≤ 3 vs. > 3 mm linear extent using LM (3.2 mm if digital microscopy is applied) might represent an important prognostic feature after radical prostatectomy. Alternatively, reporting the number of blocks with PSM 1 vs. 2 or more might also provide important prognostic data in practice.

Virchows Archiv : an international journal of pathology. 2018 Feb 16 [Epub ahead of print]

Metka Volavšek, Ana Blanca, Rodolfo Montironi, Liang Cheng, Maria R Raspollini, Nuno Vau, Jorge Fonseca, Francesco Pierconti, Antonio Lopez-Beltran

Institute of Pathology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia., Maimonides Biomedical Research Institute of Cordoba, Spain, Cordoba, Spain., Institute of Pathological Anatomy and Histopathology, School of Medicine, Polytechnic University of the Marche Region (Ancona), United Hospitals, Ancona, Italy., Department of Pathology and Laboratory Medicine, School of Medicine, Indiana University, Indianapolis, IN, USA., Histopathology and Molecular Diagnostics, University Hospital Careggi, Florence, Italy., Urologic Oncology, Champalimaud Clinical Center, Lisbon, Portugal., Urology Clinic, Champalimaud Clinical Center, Lisbon, Portugal., Division of Anatomic Pathology and Histology, Catholic University of the Sacred Heart, "Agostino Gemelli" School of Medicine, Rome, Italy., Department of Pathology, Unit of Anatomical Pathology, Department of Surgery, Faculty of Medicine, Cordoba, Spain. .