Stain normalization in digital pathology: Clinical multi-center evaluation of image quality.

In digital pathology, the final appearance of digitized images is affected by several factors, resulting in stain color and intensity variation. Stain normalization is an innovative solution to overcome stain variability. However, the validation of color normalization tools has been assessed only from a quantitative perspective, through the computation of similarity metrics between the original and normalized images. To the best of our knowledge, no works investigate the impact of normalization on the pathologist's evaluation. The objective of this paper is to propose a multi-tissue (i.e., breast, colon, liver, lung, and prostate) and multi-center qualitative analysis of a stain normalization tool with the involvement of pathologists with different years of experience. Two qualitative studies were carried out for this purpose: (i) a first study focused on the analysis of the perceived image quality and absence of significant image artifacts after the normalization process; (ii) a second study focused on the clinical score of the normalized image with respect to the original one. The results of the first study prove the high quality of the normalized image with a low impact artifact generation, while the second study demonstrates the superiority of the normalized image with respect to the original one in clinical practice. The normalization process can help both to reduce variability due to tissue staining procedures and facilitate the pathologist in the histological examination. The experimental results obtained in this work are encouraging and can justify the use of a stain normalization tool in clinical routine.

Risk of Gleason Score 3+4=7 prostate cancer upgrading at radical prostatectomy is significantly reduced by targeted versus standard biopsy.

BACKGROUND: The aim of this study is to evaluate if multiparametric magnetic resonance (mpMRI)-transrectal ultrasound (TRUS) fusion targeted biopsy (TBx) versus untargeted standard biopsy (SBx) may decrease the rate of pathological upgrading of Gleason Score (GS) 3+4 prostate cancer (PCa) at radical prostatectomy (RP). We also evaluated the impact of percent pattern 4 and cribriform glands at biopsy in the risk of GS 3+4=7 upgrading. METHODS: A total of 301 patients with GS 3+4 PCa on biopsy (159 SBx and 142 TBx) who underwent laparoscopic robot-assisted RP were sequentially enrolled. Histological data from RP sections were used as reference standard. The concordance of biopsy with pathological GS, as well as the GS 3+4 upgrading at RP were evaluated in different univariate and multivariate binary logistic regression models, testing age, PSA, fPSA%, tumor volume, PI-RADS, clinical stage, percentage of Gleason pattern 4 (GP) and/or presence of cribriform sub-type at biopsy. RESULTS: Of the 301 biopsies, the median of GP 4 was 16% of the tissue. Minimal GP 4 (≤16%) cancers had a significant lower median volume (1.7 mL) than those with GP4 >16% (2.9 mL), (P<0.001). Pathological GS 3+4 was confirmed for 58.8% and 82.2% for SBx and TBx patients, respectively. The rate of upgraded and downgraded GS on SBx versus TBx was 38.8% vis. 16.7% and 1.8% and 2.1%, respectively. The rate of upgrading was significantly associated with the presence of GP4 >16% versus ≤16% (OR 4.4, 95% CI 1.4-12.0; P=0.021) and with the presence of cribriform sub-type at biopsy specimens (OR 6.2, 95% CI 2.2-18.7; P<0.001). CONCLUSIONS: We demonstrated that TBx technique significantly reduced the risk of GS 3+4 upgrading at RP, compared to SBx one. The rate of upgrading was significantly associated with GP4>16%, mostly when cribriform sub-type was present at biopsy specimens.

Three-dimensional Elastic Augmented-reality Robot-assisted Radical Prostatectomy Using Hyperaccuracy Three-dimensional Reconstruction Technology: A Step Further in the Identification of Capsular Involvement.

BACKGROUND: In prostate cancer (PCa) surgical procedures, in order to maximize potency recovery, a nerve-sparing (NS) procedure is preferred. However, cancer abutting or focally extending beyond the prostate capsule increases the risk of a positive surgical margin. OBJECTIVE: To evaluate the accuracy of our new three-dimensional (3D) elastic augmented-reality (AR) system in identifying capsular involvement (CI) location of PCa during the NS phase of robot-assisted radical prostatectomy (RARP). Secondarily, the accuracy of this technology was compared with two-dimensional (2D)-based cognitive procedures. DESIGN, SETTING, AND PARTICIPANTS: A prospective study, enrolling 40 patients with PCa undergoing RARP at our center, from May to October 2018. SURGICAL PROCEDURE: Patients underwent 3D AR RARP or, in case of unavailability of this technology, 2D cognitive RARP. In all patients, total anatomical reconstruction was used. MEASUREMENTS: Clinical data were collected. In order to compare the two groups, nonparametric Mann-Whitney and chi-square tests were performed. A metallic clip was placed at the level of suspicious CI on the basis of images given by the 3D AR or magnetic resonance imaging (MRI) report. The pathological analysis evaluated the presence of tumor at the level of the clip. RESULTS AND LIMITATIONS: Twenty patients were enrolled in each group. Focusing on the 3D AR group at macroscopic evaluation, the metallic clip was placed at the tumor and capsular bulging in all cases. At microscopic assessment, cancer presence was confirmed in the suspicious area in 95.4% of the cases. Moreover, CI was correctly identified in 100.0% of the cases, thanks to the 3D image overlap. These results were compared with the 2D MRI cognitive group, showing, at microscopic analysis, statistically significant superiority of the 3D AR group in CI detection during the NS phase (100% vs 47.0%; p<0.05). The main limitation of this technique is that the segmentation and overlapping of the images are performed manually. CONCLUSIONS: Our findings suggest that, with the introduction of the elastic 3D virtual models, prostate deformation is correctly simulated during surgery and lesion location is correctly identified, even in dynamic reality with a subsequent potential reduction of positive surgical margin rate and, in the meantime, maximization of functional outcomes. PATIENT SUMMARY: On the basis of our findings, the three-dimensional elastic augmented-reality technology seems to help the surgeon in lesion location identification even in a dynamic phase of the intervention, optimizing the oncological outcomes.

Androgen deprivation modulates gene expression profile along prostate cancer progression.

Androgen deprivation therapy (ADT) is the standard of care for metastatic prostate cancer and initially induces tumor regression, but invariably results in castration-resistant prostate cancer through various mechanisms, incompletely discovered. Our aim was to analyze the dynamic modulation, determined by ADT, of the expression of selected genes involved in the pathogenesis and progression of prostate cancer (TMPRSS2:ERG, WNT11, SPINK1, CHGA, AR, and SPDEF) using real-time polymerase chain reaction in a series of 59 surgical samples of prostate carcinomas, including 37 cases preoperatively treated with ADT and 22 untreated cases, and in 43 corresponding biopsies. The same genes were analyzed in androgen-deprived and control LNCaP cells. Three genes were significantly up-modulated (WNT11 and AR) or down-modulated (SPDEF) in patients treated with ADT versus untreated cases, as well as in androgen-deprived LNCaP cells. The effect of ADT on CHGA gene up-modulation was almost exclusively detected in cases positive for the TMPRSS2:ERG fusion. The correlation between biopsy and surgical samples was poor for most of the tested genes. Gene expression analysis of separate tumor areas from the same patient showed an extremely heterogeneous profile in the 6 tested cases (all untreated). In conclusion, our results strengthened the implication of ADT in promoting a prostate cancer aggressive phenotype and identified potential biomarkers, with special reference to the TMPRSS2:ERG fusion, which might favor the development of neuroendocrine differentiation in hormone-treated patients. However, intratumoral heterogeneity limits the use of gene expression analysis as a potential prognostic or predictive biomarker in patients treated with ADT.