Handling of radical prostatectomy specimens

Critical evaluation of artificial intelligence as a digital twin of pathologists for prostate cancer pathology

Prostate cancer pathology plays a crucial role in clinical management but is time-consuming. Artificial intelligence (AI) shows promise in detecting prostate cancer and grading patterns. We tested an AI-based digital twin of a pathologist, vPatho, on 2603 histological images of prostate tissue stained with hematoxylin and eosin. We analyzed various factors influencing tumor grade discordance between the vPatho system and six human pathologists. Our results demonstrated that vPatho achieved comparable performance in prostate cancer detection and tumor volume estimation, as reported in the literature. The concordance levels between vPatho and human pathologists were examined. Notably, moderate to substantial agreement was observed in identifying complementary histological features such as ductal, cribriform, nerve, blood vessel, and lymphocyte infiltration. However, concordance in tumor grading decreased when applied to prostatectomy specimens (κ = 0.44) compared to biopsy cores (κ = 0.70). Adjusting the decision threshold for the secondary Gleason pattern from 5 to 10% improved the concordance level between pathologists and vPatho for tumor grading on prostatectomy specimens (κ from 0.44 to 0.64). Potential causes of grade discordance included the vertical extent of tumors toward the prostate boundary and the proportions of slides with prostate cancer. Gleason pattern 4 was particularly associated with this population. Notably, the grade according to vPatho was not specific to any of the six pathologists involved in routine clinical grading. In conclusion, our study highlights the potential utility of AI in developing a digital twin for a pathologist. This approach can help uncover limitations in AI adoption and the practical application of the current grading system for prostate cancer pathology.

Grossing and reporting of radical prostatectomy specimens: An evidence-based approach

Radical prostatectomy (RP) constitutes the primary treatment option for patients with clinically localized, biopsy-proven prostate cancer that requires local treatment with curative intent. Accurate reporting of radical prostatectomy specimens is required to guide further risk stratification and management of patients. Hence, for the handling and reporting of RP specimens, a standardized protocol should be followed. Many general pathologists may not be well-versed with the guidelines for the handling of radical prostatectomy specimens. This article discusses a detailed approach to grossing techniques, including specimen description, fixation requirements, gross cut-up, and reporting of the grade and stage of RP specimens. This will enable the pathologist to aid in multidisciplinary management.

Quantifying Tumor Heterogeneity from Multiparametric Magnetic Resonance Imaging of Prostate Using Texture Analysis

Simple Summary

Prostate cancer (PCa) occurs in males at a rate of 21.8%, predominantly at the customary primary site. High cure rates are possible through early detection and therapy when the tumor is still restricted to the prostate. These tumors do not grow rapidly, allowing for periods of up to 20 years between diagnosis and death. Multiparametric MRI (mp-MRI) is used as a non-invasive approach to diagnose PCa in subjects. This imaging method uses MR imaging with at least one functional MRI sequence to detect and characterize PCa. The use of multiparametric magnetic resonance imaging has refined the diagnosis of prostate cancer in radiology. Malignancy-modified critical features in tissue composition, such as heterogeneity, are associated with adverse tumor biology. Heterogeneity can be quantified through texture analysis, an effective technique for reviewing tumor images acquired in routine clinical practice. This study focused on identifying and quantifying tumor heterogeneity from prostate mp-MRI utilizing texture analysis.

Abstract

(1) Background: Multiparametric MRI (mp-MRI) is used to manage patients with PCa. Tumor identification via irregular sampling or biopsy is problematic and does not allow the comprehensive detection of the phenotypic and genetic alterations in a tumor. A non-invasive technique to clinically assess tumor heterogeneity is also in demand. We aimed to identify tumor heterogeneity from multiparametric magnetic resonance images using texture analysis (TA). (2) Methods: Eighteen patients with prostate cancer underwent mp-MRI scans before prostatectomy. A single radiologist matched the histopathology report to single axial slices that best depicted tumor and non-tumor regions to generate regions of interest (ROIs). First-order statistics based on the histogram analysis, including skewness, kurtosis, and entropy, were used to quantify tumor heterogeneity. We compared non-tumor regions with significant tumors, employing the two-tailed Mann–Whitney U test. Analysis of the area under the receiver operating characteristic curve (ROC-AUC) was used to determine diagnostic accuracy. (3) Results: ADC skewness for a 6 × 6 px filter was significantly lower with an ROC-AUC of 0.82 (p = 0.001). The skewness of the ADC for a 9 × 9 px filter had the second-highest result, with an ROC-AUC of 0.66; however, this was not statistically significant (p = 0.08). Furthermore, there were no substantial distinctions between pixel filter size groups from the histogram analysis, including entropy and kurtosis. (4) Conclusions: For all filter sizes, there was poor performance in terms of entropy and kurtosis histogram analyses for cancer diagnosis. Significant prostate cancer may be distinguished using a textural feature derived from ADC skewness with a 6 × 6 px filter size.

Fast prostate retrieval in robot-assisted laparoscopic prostatectomy for next-generation biobanking

Robotic-assisted laparoscopic radical prostatectomy (RALP) has become the most widespread treatment for organ-confined prostate cancer. Here, we describe a fast specimen retrieval technique for RALP to obtain high-quality tissue specimen with minimal warm ischemia time for next-generation biobanking. Here, we show that using fast retrieval technique, short warm ischemia times can be achieved while not increasing the surgical time. Patients undergoing RALP with written informed consent participated in Helsinki Urological Bank study. Previously operated RALP patients and those, who were not willing to participate in the study, served as a control group. The study consisted of 1685 patients, 684 in fast retrieval and 1001 in control group. We developed a novel fast retrieval technique in which fascia is opened for camera port according to the prostate size and a running suture is placed and tightened against the camera port in the beginning of the operation. Immediately after prostate is freed from attachments, suture is loosened and the prostate is extirpated inside the endoscopic bag through the camera port fascial opening, then the fascial suture is again tightened against the camera port and the RALP procedure is completed. The mean warm ischemia times in fast retrieval group were 20 min 18 s and 22 min 30 s, respectively, in patients without and with lymphadenectomy. The mean console and surgery times with and without lymphadenectomy were similar in both groups. There were no technique-related complications associated with Fast Retrieval procedure. Tissue integrity test results for the RNA and DNA quality showed good quality for the specimen. Fast retrieval technique can easily and safely be utilized to maximize usefulness of RALP tissue specimen in downstream biobank applications.

Effect of prostate gland weight on the surgical and oncological outcomes of extraperitoneal robot-assisted radical prostatectomy

Background

Robot-assisted radical prostatectomy (RARP) is performed by urologists as one of the surgical procedures for treating prostate cancer. Numerous studies have been published with regard to the impact of prostate weight on performing RARP but were limited by the insufficient number of patients and use of the transperitoneal approach. This study aimed to determine the effect of prostate gland weight on the surgical and short-term oncological outcomes of RARP using the extraperitoneal approach.

Methods

In total, 1168 patients who underwent extraperitoneal RARP (EP-RARP) performed by a single surgeon at Yonsei University Severance Hospital between May 2009 and May 2016 were included in the study. The patients were divided into 4 groups according to the prostate weight measured by transrectal ultrasonography preoperatively. Intraoperative and postoperative outcomes were analyzed retrospectively. One-way analysis of variance and the chi-square test were used in the statistical analyses.

Results

Age, the Gleason score, clinical stage, and pathological stage were significantly different. Patients with a larger prostate size had a longer console time and higher estimated blood loss (P < 0.05). There were no significant differences between the 4 groups in length of hospital stay, duration of catheterization, blood transfusion, body mass index, prostate-specific antigen (PSA) level, history of abdominal surgery, intraoperative complications, positive surgical margin, incidence of lymphocele, and PSA recurrence after 1 year.

Conclusions

The console time and estimated blood loss were significantly increased with a larger prostate size. However, there were no significant differences in the oncologic outcome and intraoperative complications, suggesting that EP-RARP requires meticulous bleeding control in patients with a prostate weighing > 75 g, and if appropriate management is implemented for blood loss intraoperatively, EP-RARP can be performed regardless of the prostate size.

Accuracy in local staging of prostate cancer by adding a three-dimensional T2-weighted sequence with radial reconstructions in magnetic resonance imaging

Background

The evidence supporting the use of magnetic resonance imaging (MRI) in prostate cancer detection has been established, but its accuracy in local staging is questioned.

Purpose

To investigate the additional value of multi-planar radial reconstructions of a three-dimensional (3D) T2-weighted (T2W) MRI sequence, intercepting the prostate capsule perpendicularly, for improving local staging of prostate cancer.

Material and Methods

Preoperative, bi-parametric prostate MRI examinations in 94 patients operated between June 2014 and January 2015 where retrospectively reviewed by two experienced abdominal radiologists. Each patient was presented in two separate sets including diffusion-weighted imaging, without and with the 3D T2W set that included radial reconstructions. Each set was read at least two months apart. Extraprostatic tumor extension (EPE) was assessed according to a 5-point grading scale. Sensitivity and specificity for EPE was calculated and presented as receiver operating characteristics (ROC) with area under the curve (AUC), using histology from whole-mount prostate specimen as gold standard. Inter-rater agreement was calculated for the two different reading modes using Cohen's kappa.

Results

The AUC for detection of EPE for Readers 1 and 2 in the two-dimensional (2D) set was 0.70 and 0.68, respectively, and for the 2D + 3D set 0.62 and 0.65, respectively. Inter-rater agreement (Reader 1 vs. Reader 2) on EPE using Cohen's kappa for the 2D and 2D + 3D set, respectively, was 0.42 and 0.17 (i.e. moderate and poor agreement, respectively).

Conclusion

The addition of 3D T2W MRI with radial reconstructions did not improve local staging in prostate cancer.

Prognostic significance of six clinicopathological features for biochemical recurrence after radical prostatectomy: a systematic review and meta-analysis

Identifying patients with high risk of biochemical recurrence after radical prostatectomy is of immense value in clinical practice. Assessment of prognostic significance of specific clinicopathological features plays an important role in surgical management after prostatectomy. The purpose of our meta-analysis was to investigate the association between the six pathological characteristics and the prognosis of prostate cancer. We carried out a systematic document retrieval in electronic databases to sort out appropriate studies. Outcomes of interest were gathered from studies comparing biochemical recurrence-free survival (BCFS) in patients with the six pathological traits. Studies results were pooled, and hazard ratios (HRs) combined with corresponding 95% confidence intervals (CIs) for survival were used to estimate the effect size. 29 studies (21,683 patients) were enrolled in our meta-analysis. All the six predictors were statistically significant for BCFS with regard to seminal vesicle invasion (HR = 1.97, 95% CI = 1.79–2.18, p < 0.00001), positive surgical margin (HR = 1.79, 95% CI = 1.56–2.06, p < 0.00001), extracapsular extension (HR = 2.03, 95% CI = 1.65–2.50, p < 0.0001), lymphovascular invasion (HR = 1.85, 95% CI = 1.54–2.22, p < 0.00001), lymph node involvement (HR = 1.88, 95% CI = 1.37–2.60, p = 0.0001) and perineural invasion (HR = 1.59, 95% CI = 1.33–1.91, p < 0.00001). Subgroup analysis showed that all the six predictors had significantly relationship with poor BCFS. The pooled results demonstrated that the six clinical findings indicated a worse prognosis in patients with prostate cancer. In conclusion, our results show several clinicopathological characteristics can predict the risk of biochemical recurrence after radical prostatectomy. Prospective studies are needed to further confirm the predictive value of these features for the prognosis of prostate cancer patients after radical prostatectomy.

A novel technique for biobanking of large sections of radical prostatectomy specimens

AIMS

Harvesting of unfixed tissue from radical prostatectomy specimens for research purposes is challenging. Many prostate cancers cannot be identified at gross inspection, and this tumour is notoriously multifocal and heterogeneous. We aimed to develop a technique to allow detailed topographic analysis and the sampling of a sufficient amount of tumour without jeopardising clinical reporting.

METHODS AND RESULTS

A custom-made double-bladed knife was utilised for cutting a 4-mm-thick horizontal section of the prostate. The slices were split into segments that were frozen in gel, cryosections were cut, and RNA integrity numbers (RINs) were analysed. Sections were cut from all blocks of 20 cases, and the cutting time was monitored. Slides were scanned, and the slices were digitally reconstructed. Cutting frozen sections of an entire slice took 79-253 min (mean 162 min). Tumour was detected in frozen sections of 85% (17/20) of cases and in 46% (72/155) of blocks. The morphological quality was determined to be excellent, and RIN values were high (mean 8.9).

CONCLUSIONS

This novel protocol for biobanking of fresh tissue from prostatectomy specimens provides sufficient tumour material for research purposes, while also enabling reporting of histopathology. The harvesting of a full tissue slice facilitates studies of tumour multifocality and heterogeneity.

Incidental Prostate Adenocarcinoma in Cystoprostatectomy Specimens: Partial Versus Complete Prostate Sampling

BACKGROUND

The rate of incidental prostate adenocarcinoma (PCa) detection in radical cystoprostatectomy (RCP) varies widely, ranging from 15% to 54%. Such variability may be explained by institutional differences in prostate grossing protocols. Either partial or complete submission of the prostate gland in RCP may result in detection of clinically insignificant or significant incidental PCa. The aim of the study was to compare the clinical significance of PCa in RCP specimens in partial versus complete sampling.

MATERIAL

Seventy-two out of 158 RCP cases showed incidental PCa. The pathologic features, including Gleason score, margin status, extraprostatic extension (EPE), seminal vesicle invasion (SVI), PCa stage, and tumor volume, were assessed.

RESULTS

The 72 cases were divided into partial (n = 21, 29.1%) and complete sampling (n = 51, 70.8%) groups. EPE was detected in 13/72 (18.1%) with 11/13 (84.6%) cases in the complete group. Positive margins were present in 11/72 (15.3%) with 9/11 (81.8%) in the complete group. SVI was detected in 4/72 (5.6%) with 3/4 (75.0%) in the complete group. Overall, 4/72 (5.6%) had a Gleason score >7, all of which were in the complete group.

CONCLUSION

Our data suggest that complete sampling of the prostate may be the ideal approach to grossing RCP specimens, allowing for greater detection of clinically significant incidental PCa.

Predictive factors associated with biochemical recurrence following radical prostatectomy for pathological T2 prostate cancer with negative surgical margins

OBJECTIVE

The aim of this study was to determine factors associated with the development of biochemical recurrence (BCR) following radical prostatectomy in patients with pathological T2 prostate cancer and negative surgical margins.

MATERIALS AND METHODS

This retrospective multicentre cohort study included 1252 consecutive patients with pT2 pN0/Nx and negative surgical margins on radical prostatectomy and without any adjuvant treatment, performed in three Belgian centres. BCR-free survival curves were estimated using the Kaplan-Meier method. Univariate and multivariate analyses using the Cox proportional hazards model were performed to determine clinical and pathological predictive factors of BCR in this group of patients.

RESULTS

In total, 910 patients were included. BCR occurred in 107 patients (11.8%) at a median follow-up of 108 months. Overall 5 and 10 year BCR-free survival rates were 90% and 87%, respectively. On the multivariate analyses, serum prostate-specific antigen (PSA) level (p = .001) and surgical Gleason score of 7 or above (p = .001) were significantly associated with BCR in men with pathological T2 prostate cancer with negative surgical margins. Perineural invasion and capsular infiltration were not risk factors for recurrence.

CONCLUSIONS

This study identified unfavourable risk factors in patients with pathological T2 and negative surgical margins following radical prostatectomy. The results suggest that patients with a surgical Gleason score of 7 or higher, unknown lymph-node status and high PSA values are at increased risk of recurrence.

A multi-site cutting device implements efficiently the divide-and-conquer strategy in tumor sampling

We recently showed that in order to detect intra-tumor heterogeneity a Divide-and-Conquer (DAC) strategy of tumor sampling outperforms current routine protocols. This paper is a continuation of this work, but here we focus on DAC implementation in the Pathology Laboratory. In particular, we describe a new simple method that makes use of a cutting grid device and is applied to clear cell renal cell carcinomas for DAC implementation. This method assures a thorough sampling of large surgical specimens, facilitates the demonstration of intratumor heterogeneity, and saves time to pathologists in the daily practice. The method involves the following steps: 1. Thin slicing of the tumor (by hand or machine), 2. Application of a cutting grid to the slices ( e.g., a French fry cutter), resulting in multiple tissue cubes with fixed position within the slice, 3. Selection of tissue cubes for analysis, and finally, 4. Inclusion of selected cubes into a cassette for histological processing (with about eight tissue fragments within each cassette). Thus, using our approach in a 10 cm in-diameter-tumor we generate 80 tumor tissue fragments placed in 10 cassettes and, notably, in a tenth of time. Eighty samples obtained across all the regions of the tumor will assure a much higher performance in detecting intratumor heterogeneity, as proved recently with synthetic data.

A multi-site cutting device implements efficiently the divide-and-conquer strategy in tumor sampling

We recently showed that in order to detect intra-tumor heterogeneity a Divide-and-Conquer (DAC) strategy of tumor sampling outperforms current routine protocols. This paper is a continuation of this work, but here we focus on DAC implementation in the Pathology Laboratory. In particular, we describe a new simple method that makes use of a cutting grid device and is applied to clear cell renal cell carcinomas for DAC implementation. This method assures a thorough sampling of large surgical specimens, facilitates the demonstration of intratumor heterogeneity, and saves time to pathologists in the daily practice. The method involves the following steps: 1. Thin slicing of the tumor (by hand or machine), 2. Application of a cutting grid to the slices ( e.g., a French fry cutter), resulting in multiple tissue cubes with fixed position within the slice, 3. Selection of tissue cubes for analysis, and finally, 4. Inclusion of selected cubes into a cassette for histological processing (with about eight tissue fragments within each cassette). Thus, using our approach in a 10 cm in-diameter-tumor we generate 80 tumor tissue fragments placed in 10 cassettes and, notably, in a tenth of time. Eighty samples obtained across all the regions of the tumor will assure a much higher performance in detecting intratumor heterogeneity, as proved recently with synthetic data.

Index lesion characterization by (11)C-Choline PET/CT and Apparent Diffusion Coefficient parameters at 3 Tesla MRI in primary prostate carcinoma

BACKGROUND

Index lesion characterization is important in the evaluation of primary prostate carcinoma (PPC). The aim of this study was to analyze the contribution of (11) C-Choline PET/CT and the Apparent Diffusion Coefficient maps (ADC) in detecting the Index Lesion and clinically significant tumors in PPC.

METHODS

Twenty-one untreated patients with biopsy-proven PPC and candidates for radical prostatectomy (RP) were prospectively evaluated by means of Ultra-High Definition PET/CT and 3T MRI, which included T2-weighted imaging (T2WI) and ADC maps obtained from diffusion weighted imaging (DWI). Independent experts analyzed all the images separately and were unaware of the pathological data. In each case, the Index lesion was defined as the largest tumor measured on histopathology (Index H). In addition, the largest lesion observed on MRI (Index MRI) and the highest avid (11) C-Choline uptake lesion (Index PET) were obtained. The Gleason scores (GS) of the tumors were determined. PET/CT and ADC map quantitative parameters were also calculated. Measures of correlation among imaging parameters as well as the sensitivity (S), specificity (Sp), negative and positive predictive values (NPV and PPV) for tumor detection were analyzed. All data was validated with the pathological study.

RESULTS

In the morphological study, 139 foci of carcinoma were identified, 47 of which corresponded to clinically significant tumors (>0.5 cm(3)). The remaining foci presented a maximum diameter (dmax ) of 0.1 cm ± SD 0.75 and were not classified as clinically significant. Thirty-two tumors presented a GS (3 + 3), nine GS (3 + 4), and six GS (4 + 3). A total of 21 Index H (dmax = 1.37 cm SD ± 0.61) were identified. The S, Sp, NPV, and PPV for tumor detection with PET were 100%, 70%, 83%, 100%, and for MRI were 46%, 100%, 100%, 54%, respectively. Both Index PET and Index MRI were complementary and identified 95% of the Index H when quantitative criteria were used.

CONCLUSION

In spite of the fact that PET imaging has higher tumor sensitivity than MRI, (11) C-Choline PET and ADC maps have complementary roles in the evaluation of Index Lesion in PPC. Index PET and Index MRI could be complementary targets in the therapeutic planning of PPC.

[Analysis and prognostic factors of the specimen of radical prostatectomy in prostate cancer]

OBJECTIVES

Handling and pathologic analysis of radical prostatectomy specimens are crucial to confirm the diagnosis of prostate cancer and evaluate prognostic criteria.

MATERIAL AND METHODS

A systematic review of the scientific literature was performed in the Medline database (PubMed), using different associations of the following keywords: prostate cancer; prostatectomy; specimen; handling; pathology; tumor staging; Gleason score; surgical margin; prognosis; frozen section; lymph node; biomarkers. A particular search was done on specimen management and characterization of tissue prognostic factors.

RESULTS

Handling of both radical prostatectomy specimen and lymph node dissection is standardized according to international criteria. Although the main histoprognostic factors are still Gleason score, pathologic staging and margin status, these criteria have been refined these last 10 years, allowing to improve the prediction of relapse after surgical treatment.

CONCLUSION

The standardization of handling and pathology reporting of radical prostatectomy specimens will be mandatory for treatment uniformization according to risk stratification in prostate cancer and personalization of therapeutic approaches.

Difference between actual vs. pathology prostate weight in TURP and radical robotic-assisted prostatectomy specimen

INTRODUCTION

To investigate and highlight the effect of formaldehyde induced weight reduction in transurethral resection of prostate (TURP) and radical robotically-assisted prostatectomy (RALP) specimen as a result of standard chemical fixation.

MATERIALS AND METHODS

51 patients were recruited from January 2013 to June 2013 who either underwent a TURP (n=26) or RALP (n=25). Data was collected prospectively by the operating surgeon who measured the native, unfixed histology specimen directly after operation. The specimens were fixed in 10% Formaldehyde Solution BP and sent to the pathology laboratory where after sufficient fixation period was re-weighed.

RESULTS

Overall mean age 64.78 years, TURP mean age 68.31 years RALP mean age 61.12 years. We found that the overall prostatic specimen (n=51) weight loss after fixation was a mean of 11.20% (3.78 grams) (p ≤ 0.0001). Subgroup analysis of the native TURP chips mean weight was 16.15 grams and formalin treated mean weight was 14.00 grams (p ≤ 0.0001). Therefore, TURP chips had a mean of 13.32 % (2.15 grams) weight loss during chemical fixation. RALP subgroup unfixed specimen mean weight was 52.08 grams and formalin treated mean weight was 42.60 grams (p ≤ 0.0001), a 19.32 % (9.48 grams) mean weight reduction.

CONCLUSION

It has not been known that prostatic chips and whole human radical prostatectomy specimen undergo a significant weight reduction. The practical significance of the accurate prostate weight in patient management may be limited, however, it is agreed that this should be recorded correctly, as data is potential interest for research purposes and vital for precise documentation.

Ceramic foam plates: a new tool for processing fresh radical prostatectomy specimens

Procurement of fresh tissue of prostate cancer is critical for biobanking and generation of xenograft models as an important preclinical step towards new therapeutic strategies in advanced prostate cancer. However, handling of fresh radical prostatectomy specimens has been notoriously challenging given the distinctive physical properties of prostate tissue and the difficulty to identify cancer foci on gross examination. Here, we have developed a novel approach using ceramic foam plates for processing freshly cut whole mount sections from radical prostatectomy specimens without compromising further diagnostic assessment. Forty-nine radical prostatectomy specimens were processed and sectioned from the apex to the base in whole mount slices. Putative carcinoma foci were morphologically verified by frozen section analysis. The fresh whole mount slices were then laid between two ceramic foam plates and fixed overnight. To test tissue preservation after this procedure, formalin-fixed and paraffin-embedded whole mount sections were stained with hematoxylin and eosin (H&E) and analyzed by immunohistochemistry, fluorescence, and silver in situ hybridization (FISH and SISH, respectively). There were no morphological artifacts on H&E stained whole mount sections from slices that had been fixed between two plates of ceramic foam, and the histological architecture was fully retained. The quality of immunohistochemistry, FISH, and SISH was excellent. Fixing whole mount tissue slices between ceramic foam plates after frozen section examination is an excellent method for processing fresh radical prostatectomy specimens, allowing for a precise identification and collection of fresh tumor tissue without compromising further diagnostic analysis.

Morphological Analysis of Radical Prostatectomy Specimens: Recent Topics Relevant to Prognosis

The pathology report should include clinically relevant information as well as provide clinically useful information derived from the macroscopic examination and microscopic evaluation of the radical prostatectomy (RP) specimens. The reporting pathologist should pay particular attention to the evaluation of the prognostic factors proven to be of prognostic importance and useful in clinical patient management, including histological type, grade and volume of cancer, the extent of local invasion and stage of cancer as well as the surgical margins status.

Method for sampling tissue for research which preserves pathological data in radical prostatectomy

BACKGROUND

The diagnosis and treatment of prostate cancer is a challenging global healthcare issue requiring significant molecular research. Such research frequently utilizes fresh frozen human tissue which needs to be obtained in a manner acceptable to the pathologist which does not compromise tumor diagnosis or staging.

METHODS

Radical prostatectomy specimens were handled in a standardized method before being sliced fresh. Leaving the margins intact, multiple cylindrical cores were removed using a large skin punch and the sites were marked on a prostate map. The cylindrical cores were placed onto individual, pre-numbered foil squares and snap frozen in liquid nitrogen. Prostate maps were aligned with formalin-fixed paraffin embedded hematoxylin and eosin stained sections of the sampled slice to select tumor regions. Frozen tumor tissue cylinders were processed taking one section for hematoxylin and eosin staining, 6 µm × 50 µm sections for molecular studies and a further section for hematoxylin and eosin staining. This was performed for the length of the cylinder.

RESULTS

A total of 150 prostates have been removed and sliced using this technique. Pathological assessment remained uncompromised. Using the sequential hematoxylin and eosin stained frozen sections, cellularity could be monitored closely in tissues processed for research. The yield of RNA and DNA extracted was high (tumor mean 2.4 µg (RNA) and 12.7 ng per 300 µm tissue) and of high quality (mean tumor RIN 5.9).

CONCLUSIONS

This novel, rapid sampling and processing method provides high quality tissue for research without compromising pathology.

Handling of radical prostatectomy specimens: total embedding with large-format histology

A problem when handling radical prostatectomy specimens (RPS) is that cancer is often not visible at gross examination, and the tumor extent is always underestimated by the naked eye. The challenge is increased further by the fact that prostate cancer is a notoriously multifocal and heterogeneous tumor. For the pathologist, the safest method to avoid undersampling of cancer is evidently that the entire prostate is submitted. Even though whole mounts of sections from RPS appear not to be superior to sections from standard blocks in detecting adverse pathological features, their use has the great advantage of displaying the architecture of the prostate and the identification and location of tumour nodules more clearly, with particular reference to the index tumour; further, it is easier to compare the pathological findings with those obtained from digital rectal examination (DRE), transrectal ultrasound (TRUS), and prostate biopsies. We are in favour of complete sampling of the RPS examined with the whole mount technique. There are reasons in favour and a few drawbacks. Its implementation does not require an additional amount of work from the technicians' side. It gives further clinical significance to our work of uropathologists.