Comparative analysis of sampling methods for grossing radical prostatectomy specimens performed for nonpalpable (stage T1c) prostatic adenocarcinoma

Grade Group accuracy is improved by extensive prostate biopsy sampling, but unrelated to prostatectomy specimen sampling or use of immunohistochemistry

Assessing the accurate Grade Group of a prostate needle biopsy specimen is essential for choosing the adequate therapeutic modality for prostate cancer patients. However, it is well-known that biopsy Grade Group tends to up- or downgrade significantly at radical prostatectomy. We aimed to investigate the correlation between accuracy and biopsy core number, performed immunohistochemical staining (IHC) or prostatectomy specimen sampling, with the latest also being correlated with higher detection rates of adverse pathological features, e.g., positive surgical margins, higher pathological stage or presence of perineural invasion (PnI status). The study cohort consisted of 315 consecutive patients diagnosed with prostate adenocarcinoma via transrectal ultrasound-guided needle biopsy who later underwent radical prostatectomy. We grouped and compared patients based on Grade Group accuracy, presence of IHC on biopsy, margin status, pathological stage, and PnI status. Inter-observer reproducibility was also calculated. Statistical analyzes included ANOVA, Tukey's multiple comparisons post hoc test, Chi-squared test, and Fleiss kappa statistics. Undergraded cases harboured a significantly lower number of biopsy cores (p < 0.05), than accurately graded cases. Using IHC did not affect grading accuracy significantly, nor did the number of slides from prostatectomy specimens. The mean number of slides was virtually identical when margin status, pathological stage and PnI status of prostatectomy specimens were compared. Inter-observer reproducibility at our institute was calculated as fair (overall kappa = 0.29). Grade Group accuracy is significantly improved by obtaining more cores at biopsy but is unrelated to performed IHC. The extent of sampling prostatectomy specimens, however, did not affect accuracy and failed to significantly improve detection of adverse pathological features.

Fresh tissue procurement and preparation for multicompartment and multimodal analysis of the prostate tumor microenvironment

BACKGROUND

Prostatic cancers include a diverse microenvironment of tumor cells, cancer-associated fibroblasts, and immune components. This tumor microenvironment (TME) is a known driving force of tumor survival after treatment, but the standard-of-care tissue freezing or fixation in pathology practice limit the use of available approaches/tools to study the TME's functionality in tumor resistance. Thus, there is a need for approaches that satisfy both clinical and laboratory endpoints for TME study. Here we present methods for clinical case identification, tissue processing, and analytical workflow that are compatible with standard histopathology while enabling molecular and functional interrogation of prostate TME components.

METHODS

We first performed a small retrospective review to identify cases where submission of alternate prostate tissue slices and a parallel live tissue processing protocol complement traditional histopathology and enable viable multicompartment analysis of the TME. Then, we tested its compatibility with commonly employed methods to study the microenvironment including quantification of components both in situ and after tissue dissociation. We also evaluated tissue digestion conditions and cell isolation techniques to aid various molecular and functional endpoints.

RESULTS

We identified Gleason Grade Group 3+ clinical cases where tumor volume was sufficient to allow slicing of unfixed tissue and distribution of alternating tissue slices to standard-of-care histopathology and viable multi-modal TME analyses. No single method was found that preserved cellular sub-types for all downstream readouts; instead, tissues were further divided so techniques could be catered to each endpoint. For instance, we show that incorporating the protease dispase into tissue dissociation improves viability for culture and functional analyses but hinders immune cell analysis by flow cytometry. We also found that flow activated cell sorting provides highly pure cell populations for quantitative reverse-transcription polymerase chain reaction and RNA-seq while isolation using antibody-labeled paramagnetic particles facilitated functional coculture experiments.

CONCLUSIONS

The identification of candidate cases and use of these techniques enable translational research and the development of molecular and functional assays to facilitate prostate TME study without compromising standard-of-care histopathological diagnosis. This allows bridging clinical histopathology and further interrogation of the prostate TME and promises to advance our understanding of tumor biology and unveil new predictive and prognostic markers of prostate cancer progression.

Contemporary Grading of Prostate Cancer: The Impact of Grading Criteria and the Significance of the Amount of Intraductal Carcinoma

(1) Background: Prognostic grade group (PGG) is an important prognostic parameter in prostate cancer that guides therapeutic decisions. The cribriform pattern and intraductal carcinoma (IDC) are two histological patterns, that have additional prognostic significance. However, discrepancies exist regarding the handling of IDC according to the guidelines published by two international genitourinary pathology societies. Furthermore, whether, in addition to its presence, the amount of IDC is also of importance has not been studied before. Lastly, the handling of tertiary patterns has also been a matter of debate in the literature. (2) Methods: A total of 129 prostatectomy cases were retrieved and a detailed histopathologic analysis was performed. (3) Results: Two cases (1.6%) upgraded their PGG, when IDC was incorporated in the grading system. The presence and the amount of IDC, as well as the presence of cribriform carcinoma were associated with adverse pathologic characteristics. Interestingly, in six cases (4.7%) there was a difference in PGG when using the different guidelines regarding the handling of tertiary patterns. In total, 6.2% of the cases would be assigned a different grade depending on the guidelines followed. (4) Conclusions: These findings highlight a potential area of confusion among pathologists and clinicians and underscore the need for a consensus grading system.

Added Clinical Value of Whole-mount Histopathology of Radical Prostatectomy Specimens: A Collaborative Review

CONTEXT

Whole-mount histopathology, that is, large format histology or whole-mount sectioning, refers to the histopathological examination of tissue sections from specimens processed with large tissue cassette. In some institutions, it is applied routinely to specimens with genitourinary cancers.

OBJECTIVE

To give an overview of the application of the large format histology to the morphological examination of the radical prostatectomy (RP) specimens.

EVIDENCE ACQUISITION

A comprehensive PubMed search was performed up to May 2020, using the keywords "prostate carcinoma," "radical prostatectomy specimens," "whole-mount histopathology," "whole mount sectioning," "large format histology," "macrosectioning," "diagnostic criteria," and "prognosis." The search, supplemented with a hand search, was restricted to articles published in the English language. No limitations were placed on the publication year. References in relevant articles were also reviewed.

EVIDENCE SYNTHESIS

Even though the whole-mount sections of RPs appear not to be superior to regular sections in detecting adverse pathological features, their use has the advantage of displaying the architecture of the prostate gland and identifying and locating tumor nodule(s) more clearly, with particular reference to the index tumor. Further, it is easier to compare the pathological features with clinical findings derived, for instance, from digital rectal examination, transrectal ultrasound, multiparametric magnetic resonance imaging, surgical operation, and prostate biopsies.

CONCLUSIONS

Urologists, radiologists, and oncologists are updated about the step forward made by pathologists when diagnostic and prognostic information is derived from an approach that closely resembles that used by the clinicians when dealing with imaging findings.

PATIENT SUMMARY

Adoption of the whole-mount histopathology adds clinical value in correlation with clinical/imaging findings of radical prostatectomy specimens.

Multifocal Extraprostatic Extension of Prostate Cancer

OBJECTIVES

To investigate the prognostic utility of multifocal extraprostatic extension (EPE) on biochemical recurrence after radical prostatectomy.

METHODS

We conducted retrospective analysis of biochemical recurrence and prognostic pathologic variables in 673 men with stage pT3a/pT3b prostate cancer from 2000 to 2012. Extent of EPE on radical prostatectomy was divided into three groups: focal EPE (tumor dimension <0.8 mm), established (≥ 0.8 mm), and multifocal (more than one focus of EPE <0.8 mm).

RESULTS

Type of EPE had significant effect on recurrence with progressively lower progression-free probability and higher recurrence probability from focal to established to multifocal. Multifocal and established tumors exhibited worse prognostic features and higher hazard ratio than focal. In multivariate analysis, established and multifocal were independent prognostic factors with the greatest adverse prognostic significance associated with multifocal.

CONCLUSIONS

Identification of multifocal EPE provides important prognostic information associated with increased likelihood of recurrence compared to focal and established tumors.

Gleason score 5 + 3 = 8 (grade group 4) prostate cancer-a rare occurrence with contemporary grading

Grade Group (GG) 4 prostate cancer includes Gleason scores (GS) 3 + 5 = 8, 4 + 4 = 8, and 5 + 3 = 8. Some studies without pathology re-review of historical cohorts proposed that the presence of pattern 5 worsens prognosis compared to GS 4 + 4 = 8 cancer. We assessed how often historically graded GS 5 + 3 = 8 cancers retain this grade with contemporary grading recommendations. Sixteen prostate biopsies and 24 radical prostatectomies (RP) reported from 2005 to 2019 as GS 5 + 3 = 8 were re-reviewed and graded according to contemporary recommendations. In discrepant cases, an attempt was made to explain the different grading. One (6%) biopsy and 3 (12%) RPs remained GS 5 + 3 = 8 (GG4) after re-review. Two (12%) biopsies remained GG4 but were re-graded as GS 3 + 5 = 8 and 1 (4%) RP was reclassified as GS 4 + 4 = 8 (GG4). Eight (50%) biopsies and 15 (64%) RPs were upgraded to Gleason scores 9-10 (GG5). Five (32%) biopsies and 1 (4%) RPs were downgraded to Gleason score 7 (GG2 and 3). One (4%) RP showed GS 3 + 3 = 6 (GG1) cancer. Data from 2013-current from the 3 institutions were available to assess the incidence of GS 5 + 3 = 8 following re-review of the cases. Out of 14 359 biopsies with cancer and 6727 radical prostatectomy specimens, only 1 case (0.007%) and no cases (0%) were graded as GS 5 + 3 = 8, respectively. Reasons for grading discrepancies included: 1) assigning an overall common grade to separate needle cores or tumor nodules; 2) inclusion of <5% lower grade pattern into grading; and 3) misinterpretation of variant histology and patterns. Challenging patterns were poorly-formed glands, signet ring cell-like features, atrophic carcinoma, ductal carcinoma, and mucinous fibroplasia. GS 5 + 3 = 8 (GG4) cancer is very rare with contemporary grading. The reliability of conclusions from retrospective databases regarding the clinical significance of this grade combination without slide re-review is questionable.

Urinary DNA methylation biomarkers for prediction of prostate cancer upgrading and upstaging

Background

Significant numbers of prostate cancer (PCa) patients experience tumour upstaging and upgrading in surgical specimens that cause serious problems in timely and proper selection of the treatment strategy. This study was aimed at the evaluation of a set of established epigenetic biomarkers as a noninvasive tool for more accurate PCa categorization before radical prostatectomy (RP).

Methods

Quantitative methylation-specific PCR was applied for the methylation analysis of RARB, RASSF1, and GSTP1 in 514 preoperatively collected voided or catheterized urine samples from the single-centre cohort of 1056 treatment-naïve PCa patients who underwent RP. The rates of biopsy upgrading and upstaging were analysed in the whole cohort.

Results

Pathological examination of RP specimens revealed Gleason score upgrading in 27.2% and upstaging in 20.3% of the patients with a total misclassification rate of 39.0%. DNA methylation changes in at least one gene were detected in more than 80% of urine samples. Combination of the PSA test with the three-gene methylation analysis in urine was a significant predictor of pathological upstaging and upgrading (P < 0.050), however, with limited increase in overall accuracy. The PSA test or each gene alone was not informative enough.

Conclusions

The urinary DNA methylation assay in combination with serum PSA may predict tumour stage or grade migration post-RP aiding in improved individual risk assessment and appropriate treatment selection. Clinical utility of these biomarkers should be proven in larger multi-centre studies.

Electronic supplementary material

The online version of this article (10.1186/s13148-019-0716-z) contains supplementary material, which is available to authorized users.

Focused Submission of Tissue for Radical Prostatectomy Following Multiparametric Magnetic Resonance Imaging/Ultrasound Fusion-Targeted Biopsy

Prostate cancer can be difficult to appreciate grossly and therefore partial sampling of the gland can lead to incorrect grading, staging, or margin status. However, submitting the entire prostate is more time consuming and costly. We investigated the use of magnetic resonance imaging/ultrasound-targeted biopsy for the selective submission of prostatectomy specimens. We performed a retrospective review for patients with cancer on targeted prostate biopsy who underwent subsequent radical prostatectomy. Prostatectomy specimens were submitted in their entirety and assessed for Grade Group, extraprostatic extension (EPE), margins, and number of blocks. For Targeted-Grossing (TG) assessment, apex margin, bladder neck margin, seminal vesicles, and vas deferens sections were included. For the remainder of the prostate, only sections from areas shown to be positive for cancer on targeted biopsy were included in the analysis. With total tissue submission, EPE was found in 39/81 (48.1%) cases and positive margins in 19/81 (23.5%) cases. The TG method required significantly fewer blocks: 15.8 ± 5.9 versus 44.9 ± 11.9 (P < .0001). The TG method would have diagnosed the correct stage in 73/81 (90.1%) cases, Grade Group in 74/81 (91.4%) cases, and margin status in 79/81 (97.5%) cases. EPE was missed completely by the TG method in 7 cases (P = .008), of which 5/7 (71.4%) had focal EPE. There was no significant difference in stage (P = .24), Grade Group (P = .95), or margin status (P = .16) between the 2 methods. Grossing utilizing selective tissue submission from areas found to be positive for prostate cancer on magnetic resonance imaging/ultrasound-targeted prostate biopsy remains inferior to complete submission of tissue for radical prostatectomy specimens.

Partial versus complete prostatectomy specimen sampling: prospective non-inferiority study for pT3a tumours and surgical margin involvement

AIMS

The importance of additional information gained by complete versus partial sampling or prostatectomy specimens is uncertain. There is sparse data on the value of complete versus partial sampling and numbers of inclusions in studies are small and retrospective. We present the results of a prospective non-inferiority study to examine if partial sampling is inferior to complete sampling in terms of pathology outcomes and clinical relevance.

METHODS

564 robot-assisted prostatectomy (RARP) specimens with prospective registration and analysis were collected over a 2-year period. All patients underwent RARP between January 2014 and February 2016 in our hospital after a diagnosis of clinically localised prostate cancer. For each patient, tumour stage and surgical margin status was recorded after partial and after complete sampling. Upstaging from pT2 to pT3a and upgrading from a negative-to-positive surgical margin was analysed.

RESULTS

In 12 of 564 patients (2.1%), complete sampling yielded new information. In eight patients (1.4%), the surgical margin converted to positive after complete sampling. Upstaging from initial pT2 tumour in partial sampling to pT3a tumour after complete sampling was documented in five patients (0.9%). In the follow-up period (mean 35 months), a biochemical recurrence occurred in one patient.

CONCLUSIONS

Complete sampling provides new information in only 2.1% of cases, compared with partial sampling. We conclude that the additional information gained by complete sampling in terms of stage and surgical margin detection is statistically insignificant compared with partial sampling. Furthermore, partial sampling compared with complete sampling does not change postoperative clinical management.

Defining clinically significant prostate cancer on the basis of pathological findings

The definition of clinically significant prostate cancer is a dynamic process that was initiated many decades ago, when there was already evidence that a great proportion of patients with prostate cancer diagnosed at autopsy never had any clinical symptoms. Autopsy studies led to examinations of radical prostatectomy (RP) specimens and the establishment of the definition of significant cancer at RP: tumour volume of 0.5 cm³ , Gleason grade 6 [Grade Group (GrG) 1], and organ-confined disease. RP studies were then used to develop prediction models for significant cancer by the use of needle biopsies. The first such model was used to delineate the first active surveillance (AS) criteria, known as the 'Epstein' criteria, in which patients with a cancer Gleason score of 3 + 3 = 6 (GrG1) involving fewer than two cores, and <50% of any given core, and a prostate-specific antigen density of <0.15 ng/ml per cm³ had a minimal risk of significant cancer at RP. These were adopted as components of the 'very-low-risk category' of the National Comprehensive Cancer Network guidelines, in which AS is supported as a management option. With the increase in the popularity of AS, much research has been carried out to better define significant/insignificant cancer, in order to be able to safely offer AS to a larger proportion of patients without the risk of undertreatment. Research has focused on allowing higher volume tumours, focal extraprostatic extension, and a limited amount of Gleason pattern 4, and the significance of different morphological patterns of Gleason 4. Other areas of research that will probably impact on the field but that are not covered in this review include the molecular classification of tumours and imaging techniques.

Marked Prognostic Impact of Minimal Lymphatic Tumor Spread in Prostate Cancer

BACKGROUND

Nodal metastasis (N1) is a strong prognostic parameter in prostate cancer; however, lymph node evaluation is always incomplete.

OBJECTIVE

To study the prognostic value of lymphatic invasion (L1) and whether it might complement or even replace lymph node analysis in clinical practice.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective analysis of pathological and clinical data from 14 528 consecutive patients.

INTERVENTION

Radical prostatectomy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The impact of L1 and N1 on patient prognosis was measured with time to biochemical recurrence as the primary endpoint.

RESULTS AND LIMITATIONS

Nodal metastases were found in 1602 (12%) of 13 070 patients with lymph node dissection. L1 was seen in 2027 of 14 528 patients (14%) for whom lymphatic vessels had been visualized by immunohistochemistry. N1 and L1 continuously increased with unfavorable Gleason grade, advanced pT stage, and preoperative prostate-specific antigen (PSA) values (p<0.0001 each). N1 was found in 4.3% of 12 501 L0 and in 41% of 2027 L1 carcinomas (p<0.0001). L1 was seen in 11% of 9868 N0 and in 61% of 1360 N1 carcinomas (p<0.0001). Both N1 and L1 were linked to PSA recurrence (p<0.0001 each). This was also true for 17 patients with isolated tumor cells (ie, <200 unequivocal cancer cells without invasive growth) and 193 metastases ≤1mm. Combined analysis of N and L status showed that L1 had no prognostic effect in N1 patients but L1 was strikingly linked to PSA recurrence in N0 patients. N0L1 patients showed a similar outcome as N1 patients.

CONCLUSIONS

Analysis of lymphatic invasion provides comparable prognostic information than lymph node analysis. Even minimal involvement of the lymphatic system has pivotal prognostic impact in prostate cancer. Thus, a thorough search for lymphatic involvement helps to identify more patients with an increased risk for disease recurrence.

PATIENT SUMMARY

Already minimal amounts of tumor cells inside the lymph nodes or intraprostatic lymphatic vessels have a severe impact on patient prognosis.

Prostate cancer grading: a decade after the 2005 modified system

This review article will cover the evolution of grading of prostate cancer from the original Gleason system in the 1960-1970s to a more patient-centric grading system proposed in 2013 from a group at Johns Hopkins Hospital, validated in 2014 by a large multi-institutional study, and subsequently accepted by the World Health Organization (WHO), College of American Pathology (CAP), and the AJCC TNM system. Covered topics include: (1) historical background; (2) 2005 and 2014 International Society of Urological Pathology Grading Conferences; (3) Description of Gleason patterns; (4) new approaches to display Gleason grades; (5) grading variants and variations of acinar adenocarcinoma; (6) reporting rules for Gleason grading reporting secondary patterns of higher grade when present to a limited extent; (7) reporting secondary patterns of lower grade when present to a limited extent; (8) reporting percentage pattern 4; (9) general applications of the Gleason grading system; (10) needle biopsy with different cores showing different grades; (11) radical prostatectomy specimens with separate tumor nodules; and (12) a new grading system for prostate cancer.

Light-sheet microscopy for slide-free non-destructive pathology of large clinical specimens

For the 1.7 million patients per year in the U.S. who receive a new cancer diagnosis, treatment decisions are largely made after a histopathology exam. Unfortunately, the gold standard of slide-based microscopic pathology suffers from high inter-observer variability and limited prognostic value due to sampling limitations and the inability to visualize tissue structures and molecular targets in their native 3D context. Here, we show that an open-top light-sheet microscope optimized for non-destructive slide-free pathology of clinical specimens enables the rapid imaging of intact tissues at high resolution over large 2D and 3D fields of view, with the same level of detail as traditional pathology. We demonstrate the utility of this technology for various applications: wide-area surface microscopy to triage surgical specimens (with ~200 μm surface irregularities), rapid intraoperative assessment of tumour-margin surfaces (12.5 sec/cm2), and volumetric assessment of optically cleared core–needle biopsies (1 mm in diameter, 2 cm in length). Light-sheet microscopy can be a versatile tool for both rapid surface microscopy and deep volumetric microscopy of human specimens.

Grading of prostatic adenocarcinoma: current state and prognostic implications

Background

Despite significant changes in the clinical and histologic diagnosis of prostate cancer, the Gleason grading system remains one of the most powerful prognostic predictors in prostate cancer. The correct diagnosis and grading of prostate cancer is crucial for a patient’s prognosis and therapeutic options. However, this system has undergone significant revisions and continues to have deficiencies that can potentially impact patient care.

Main Body

We describe the current state of grading prostate cancer, focusing on the current guidelines for the Gleason grading system and recent changes from the 2014 International Society of Urological Pathology Consensus Conference on Gleason Grading of Prostatic Carcinoma. We also explore the limitations of the current Gleason grading system and present a validated alternative to the Gleason score. The new grading system initially described in 2013 in a study from Johns Hopkins Hospital and then validated in a multi-institutional study, includes five distinct Grade Groups based on the modified Gleason score groups. Grade Group 1 = Gleason score ≤6, Grade Group 2 = Gleason score 3 + 4 = 7, Grade Group 3 = Gleason score 4 + 3 = 7, Grade Group 4 = Gleason score 8, Grade Group 5 = Gleason scores 9 and 10.

Conclusion

As this new grading system is simpler and more accurately reflects prostate cancer biology, it is recommended by the World Health Organization (WHO) to be used in conjunction with Gleason grading.

Assessment of the circumferential margins, extraprostatic extension and Gleason score in radical prostatectomy specimens: Comparison of a partial embedding method with supplemental total inclusion of peripheral tissues

BACKGROUND

Recent data suggest that up to 21% of positive circumferential margins (PCM) and 47% of extraprostatic extension (EPE) samples may be missed when partial embedding methods are employed. Kim and colleagues (2009) suggested that total inclusion of the periphery (3mm rim) of the prostate prevented the failure to detect PCM and EPE.

DESIGN

Radical prostatectomy specimen (n=148) slides were reviewed after adoption of a protocol that included a ∼3 mm rim of peripheral tissues. We evaluated whether the analysis of supplemental slides of prostate periphery changed margin status, presence of EPE, Gleason score and extent of PCM and EPE.

RESULTS

Partial sampling resulted in missing 29% of PCM and 20% of EPE without using data from the supplemental slides of prostate periphery. Changes from focal to extensive disease were found in 11/21 (52%) cases of positive circumferential margins and in 5/13 (38%) cases of extraprostatic extension. Changes in the Gleason score were uncommon.

CONCLUSIONS

These results indicate the importance of including all the prostate peripheral tissue for microscopic analysis when partial embedding methods are adopted.

Prostate Cancer Grading: A Decade After the 2005 Modified Gleason Grading System

Since 1966, when Donald Gleason, MD, first proposed grading prostate cancer based on its histologic architecture, there have been numerous changes in clinical and pathologic practices relating to prostate cancer. Patterns 1 and 2, comprising more than 30% of cases in the original publications by Gleason, are no longer reported on biopsy and are rarely diagnosed on radical prostatectomy. Many of these cases may even have been mimickers of prostate cancer that were described later with the use of contemporary immunohistochemistry. The original Gleason system predated many newly described variants of prostate cancer and our current concept of intraductal carcinoma. Gleason also did not describe how to report prostate cancer on biopsy with multiple cores of cancer or on radical prostatectomy with separate tumor nodules. To address these issues, the International Society of Urological Pathology first made revisions to the grading system in 2005, and subsequently in 2014. Additionally, a new grading system composed of Grade Groups 1 to 5 that was first developed in 2013 at the Johns Hopkins Hospital and subsequently validated in a large multi-institutional and multimodal study was presented at the 2014 International Society of Urological Pathology meeting and accepted both by participating pathologists as well as urologists, oncologists, and radiation therapists. In the present study, we describe updates to the grading of prostate cancer along with the new grading system.

Optimizing prostate specimen handling for diagnosis and prognosis

Optimal processing, handling, and sampling of prostatic biopsies, transurethral resections, and radical prostatectomy specimens ensure accurate diagnosis and staging. Prognostic factors derived from careful examination of tissue samples are critical for patient management, including cancer volume, extraprostatic extension, surgical margins, vascular/lymphatic invasion, and perineural invasion. This chapter addresses these important issues, including recent recommendations of a consensus panel of the International Society of Urologic Pathologists.

A modified point count method as a practical approach to assess the tumor volume and the percent gland involvement by prostate carcinoma

This study reports a modified point-count method for quantifying the extent of carcinoma in prostatectomy specimens (n=143), as adapted from Billis et al. (2003) [3]. The prostates were studied as follows: the basal/apical margins were sampled using the cone method. The remainder of the gland was divided into 12 quadrant-shaped regions that were sampled using two slices. Eight equidistant points were marked directly on the coverslip over each fragment. The points inside the tumoral areas were counted and expressed as both the percentage of prostate gland involvement by carcinoma (PGI) and the tumor volume (TV). A significant correlation between the preoperative PSA levels and each of the three quantitative estimations were observed, with improved correlations with the PGI and TV values obtained using the point-count method (viz. number of slices involved (NSI) (r=0.32), PGI (r=0.39) and TV (r=0.44)). With the data sets stratified into three categories, all three methods correlated with multiple parameters, including Gleason scores ≥7, primary Gleason scores ≥4, perineural/angiolymphatic invasion, extraprostatic extension, seminal vesicle invasion and positive margins. All three quantitative methods were associated with morphologic features of tumor progression. The results obtained using this modified point-count method correlate more strongly with preoperative PSA levels.

Partial sampling of radical prostatectomy specimens: detection of positive margins and extraprostatic extension

Currently there is no global agreement as to how extensively a radical prostatectomy specimen should be sectioned and histologically examined. We analyzed the ability of different methods of partial sampling in detecting positive margin (PM) and extraprostatic extension (EPE)-2 pathologic features of prostate cancer that are most easily missed by partial sampling of the prostate. Radical prostatectomy specimens from 617 patients treated with open radical prostatectomy between 1992 and 2011 were analyzed. Examination of the entirely submitted prostate detected only PM in 370 (60%), only EPE in 100 (16%), and both in 147 (24%) specimens. We determined whether these pathologic features would have been diagnosed had the examination of the specimen been limited only to alternate sections (method 1), alternate sections representing the posterior aspect of the gland in addition to one of the mid-anterior aspects (method 2), and every section representing the posterior aspect of the gland in addition to one of the mid-anterior aspects, supplemented by the remaining ipsilateral anterior sections if a sizeable tumor is seen (method 3). Methods 1 and 2 missed 13% and 21% of PMs and 28% and 47% of EPEs, respectively. Method 3 demonstrated better results missing only 5% of PMs and 7% of EPEs. Partial sampling techniques missed slightly more PMs and EPEs in patients with low-risk to intermediate-risk prostate cancer, although even in high-risk cases none of the methods detected all of the studied aggressive pathologic features.

Next-generation prostate cancer biobanking: toward a processing protocol amenable for the International Cancer Genome Consortium

Next-generation DNA and RNA sequencing requires intact nucleic acids from high-quality human tissue samples to better elucidate the molecular basis of cancer. We have developed a prostate biobanking protocol to acquire suitable samples for sequencing without compromising the accuracy of clinical diagnosis. To assess the clinical implications of implementing this protocol, we evaluated 105 consecutive radical prostatectomy specimens from November 2008 to February 2009. Alternating levels of prostate samples were submitted to Surgical Pathology as formalin-fixed, paraffin-embedded blocks and to the institutional biobank as frozen blocks. Differences in reported pathologic characteristics between clinical and procured specimens were compared. Clinical staging and grading were not affected by the biobank protocol. Tumor foci on frozen hematoxylin and eosin slides were identified and high-density tumor foci were scored and processed for DNA and RNA extractions for sequencing. Both DNA and RNA were extracted from 22 cases of 44 with high-density tumor foci. Eighty-two percent (18/22) of the samples passed rigorous quality control steps for DNA and RNA sequencing. To date, DNA extracted from 7 cases has undergone whole-genome sequencing, and RNA from 18 cases has been RNA sequenced. This protocol provides prostate tissue for high-throughput biomedical research and confirms the feasibility of actively integrating prostate cancer into The Cancer Genome Atlas Program, a member of the International Cancer Genome Consortium.

Quantitative RT-PCR analysis of PSA and prostate-specific membrane antigen mRNA to detect circulating tumor cells improves recurrence-free survival nomogram prediction after radical prostatectomy

BACKGROUND

Circulating tumor cell (CTC) analysis is a potential new biomarker in prostate cancer. We hypothesize that quantitative detection of CTCs in patients pre- and post-radical prostatectomy (RP) using quantitative TaqMan® fluorogenic RT-PCR will improve the accuracy of the Kattan nomogram to predict the probability of recurrence-free survival (RFS) post-RP.

METHODS

Ninty-two patients who underwent RP between 2004 and 2009 had venous blood samples taken pre- (Day - 1) and post-operatively (Day + 7). We performed quantitative Taqman® RT-PCR to detect circulating prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSMA) mRNA. We calculated both the logarithmic ratio of Day + 7/Day - 1 for PSA (PSAr) and PSMA (PSMAr) expression (log(Day+7/Day-1) ) and the Kattan nomogram predicted probability of disease recurrence for each patient. We then analyzed how the AUC-ROC analysis for the Kattan nomogram prediction alone (K) compared to the addition of the PSAr and PSMAr in predicting 5-year RFS.

RESULTS

The mean age (years), PSA (ng/ml), and follow-up (mo) was 65.1, 9.13, and 72, respectively. The AUCs for K, PSAr + K, and PSMAr + K were 0.752 (95%CI 0.620-0.860), 0.830 (95%CI 0.740-0.911), and 0.837 (95%CI 0.613-0.923), respectively (P = 0.03). The Kattan 5-year PSA RFS was 75%. The actual 5-year PSA RFS survival rate was 77%.

CONCLUSIONS

Data from modern quantitative RT-PCR to detect circulating prostate-derived PSA and PSM mRNA pre- and post-RP improves the accuracy of the Kattan nomogram to predict biochemical recurrence.

Impact of surgical margin status on prostate-cancer-specific mortality

Study Type--Diagnostic (exploratory cohort) Level of Evidence 2b. What's known on the subject? and What does the study add? Surgical margin status at radical prostatectomy (RP) has been shown to be a predictor of disease progression and the strongest predictor of benefit from adjuvant therapy, but the impact of a positive surgical margin (PSM) on long-term prostate-cancer-specific survival is unknown. The PSM rate is dependent on the pathological stage of the cancer. In a recent multicentre nomogram for 15-year prostate-cancer-specific mortality (PCSM) after RP, PSM was not significantly associated with PCSM, while Gleason score and pathological stage were the only significant predictors. This has not been validated in a single centre, and PSM has been shown to vary greatly with surgical technique. This is the first study on the impact of PSM on PCSM in a single surgeon's cohort. In other centres, the decision to administer adjuvant therapy may be influenced by surgical margin status. In this cohort, men routinely did not receive adjuvant therapy, affording the unique opportunity to study the long-term implications of a PSM.

OBJECTIVE

• To examine the relative impact of a positive surgical margin (PSM) and other clinicopathological variables on prostate-cancer-specific mortality (PCSM) in a large retrospective cohort of patients undergoing radical prostatectomy (RP).

PATIENTS AND METHODS

• Between 1982 and 2011, 4569 men underwent RP performed by a single surgeon. • Of the patient population, 4461 (97.6%) met all the inclusion criteria. • The median (range) age was 58 (33-75) years and the median prostate-specific antigen (PSA) was 5.4 ng/mL; RP Gleason score was ≤ 6 in 2834 (63.7%), 7 in 1351 (30.3%), and 8-10 in 260 (6.0%) patients; PSMs were found in 462 (10.4%) patients. • Cox proportional hazards models were used to determine the impact of a PSM on PCSM.

RESULTS

• At a median (range) follow-up of 10 years (1-29), 187 men (4.3%) had died from prostate cancer. • The 20-year prostate-cancer-specific survival rate was 75% for those with a PSM and 93% for those without. • Compared with those with a negative surgical margin, men with a PSM were more likely to be older (median age 60 vs 58 years) and to have undergone RP in the pre-PSA era (36.6% vs 11.8%). Additionally, they were more likely to have a higher PSA level (median 7.6 vs 5.2 ng/mL), a Gleason score of ≥ 7 (58.7% vs 33.7%), and a non-organ-confined tumour (90.9% vs 30.6% [P < 0.001 for all]). • In a univariate model for PCSM, PSM was highly significant (hazard ratio [HR] 5.0, 95% confidence interval [CI] 3.7-6.7, P < 0.001). • In a multivariable model, adjusting for pathological variables and RP year, PSM remained an independent predictor of PCSM (HR 1.4, 95% CI 1.0-1.9, P = 0.036) with a modest effect relative to RP Gleason score (HR 5.7-12.6) and pathological stage (HR 2.2-11.0 [P < 0.001]).

CONCLUSION

• Although a PSM has a statistically significant adverse effect on prostate-cancer-specific survival in multivariable analysis, Gleason grade and pathological stage were stronger predictors.

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.

Processing radical prostatectomies: an alternate-slice method is comparable with total embedding

Receipt of radical prostatectomy specimens in the histopathology laboratory is quite common in academic centers and community hospitals. Despite numerous processing protocols, there is not an accepted standard method of processing. There are potential disadvantages of total sampling of the prostate; however, other alternatives have not been proven to show significant advantages. We present a partial sampling method (alternate slice) and compare its results to the total embedding method. Consecutive radical prostatectomy specimens were selected to compare both histologic sampling methods. The primary method of sampling was total embedding. Subsequently, alternate slice sections from the anterior, middle, and posterior thirds of the gland were reviewed. Seminal vesicle, bladder neck, and margins were similarly evaluated in both methods. Total sampling resulted in an average of 30 blocks compared with 18 in the alternate slice method. Gleason correlation was 87.5%; extraprostatic extension correlation was 97.9%. There was complete correlation in margin status and perineural invasion. Pathologic staging correlation was 97.9%. In summary, this alternate slice method compares very favorably with the total embedding method.

Solitary and small (≤3 mm) apical positive surgical margins are related to biochemical recurrence after radical prostatectomy

OBJECTIVES

To evaluate the prognostic value of positive surgical margins (PSM) in radical prostatectomy (RPE) specimens in relation to multifocality, localization and size.

METHODS

A total of 1036 patients who underwent RPE and staged pT2-3a,pN0,M0 were evaluated. None had received adjuvant or neoadjuvant therapy. All specimens were routinely processed by complete whole mount sectioning. Exact number, localization and size of PSM were reassessed, and patients were followed up for a mean of 60 months.

RESULTS

A total of 267 patients (26%) showed PSM (20% pT2, 48% pT3a). Preoperative prostate-specific antigen, Gleason score (GS) and PSM were independent predictors of biochemical recurrence (BCR). BCR-free survival rates for patients with and without PSM were 59% and 80%, respectively (HR 2.1; P < 0.001). PSM were related to biochemical failure in pT2 and pT3a tumors (P = 0.001 and P = 0.015). A total of 64% of solitary PSM were apical. Multifocality, localization and size of PSM had no significant impact on BCR.

CONCLUSIONS

Solitary apical and small PSM in RPE have a significant impact on BCR-free survival in localized stages.

International Society of Urological Pathology (ISUP) Consensus Conference on Handling and Staging of Radical Prostatectomy Specimens. Working group 1: specimen handling

The 2009 International Society of Urological Pathology Consensus Conference in Boston made recommendations regarding the standardization of pathology reporting of radical prostatectomy specimens. Issues relating to the handling and processing of radical prostatectomy specimens were coordinated by working group 1. Most uropathologists followed similar procedures for fixation of radical prostatectomy specimens, with 51% of respondents transporting tissue in formalin. There was also consensus that the prostate weight without the seminal vesicles should be recorded. There was consensus that the surface of the prostate should be painted. It was agreed that both the prostate apex and base should be examined by the cone method with sagittal sectioning of the tissue sample. There was consensus that the gland should be fully fixed before sectioning. Both partial and complete embedding of prostates was considered to be acceptable as long as the method of partial embedding is stated. No consensus was determined regarding the necessity of weighing and measuring the length of the seminal vesicles, the preparation of whole mounts rather than standardized blocks and the methodology for sampling of fresh tissue for research purposes, and it was agreed that these should be left to the discretion of the working pathologist.

Positive surgical margins at radical prostatectomy predict prostate cancer specific mortality

PURPOSE

Positive surgical margins in men undergoing radical prostatectomy for prostate cancer are associated with an increased risk of biochemical recurrence. Few data are available on the role of positive surgical margins in prostate cancer specific mortality. Using a large, population based national cancer registry we evaluated the risk of prostate cancer specific mortality associated with margin status.

MATERIALS AND METHODS

The SEER cancer registry data for patients diagnosed between 1998 and 2006 were used to identify men undergoing radical prostatectomy for prostate cancer. Margin status, pathological stage, Gleason grade and postoperative radiation therapy were recorded along with demographic data. Multivariate Cox regression analysis was used to estimate the risk of prostate cancer specific mortality associated with positive surgical margins.

RESULTS

A total of 65,633 patients comprised the cohort in which 291 (0.44%) prostate cancer specific deaths occurred during an average followup of 50 months. Positive surgical margins were reported in 21.2% of cases and were more common in pT3a than pT2 tumors (44% vs 18%, p <0.001) and higher grade tumors (28% vs 18%, p <0.001). The 7-year disease specific survival rates for those at highest risk for prostate cancer specific mortality (higher grade pT3a) were 97.6% for cases with negative surgical margins and 92.4% for those with positive surgical margins. Positive surgical margins were associated with a 2.6-fold increased unadjusted risk of prostate cancer specific mortality (HR 2.55, 95% CI 2.02-3.21). Positive surgical margins remained an independent predictor of prostate cancer specific mortality on multivariate analysis (HR 1.70, 95% CI 1.32-2.18).

CONCLUSIONS

These data demonstrate the independent role of positive surgical margins in prostate cancer specific mortality. These findings support the importance of optimizing surgical techniques to achieve a sound oncological surgical outcome with negative surgical margins when possible.

Limited sampling of radical prostatectomy specimens with excellent preservation of prognostic parameters of prostate cancer

CONTEXT

The widespread use of the serum prostate-specific antigen test has increased the early detection of prostate cancer and consequently reduced grossly definable prostate cancers.

OBJECTIVE

To find the most efficient gross sampling method for radical prostatectomy specimens not only preserving important prognostic factors but also being cost effective.

DESIGN

We initially analyzed clinicopathologic features of the entire prostate sections from 148 radical prostatectomy specimens, which then were used to examine the impact of 5 partial sampling methods on tumor stage, Gleason score, extraprostatic extension, resection margin status, and paraffin block numbers. The methods included submission of (1) alternative slices, (2) alternative slices plus biopsy-positive posterior quarters, (3) every posterior half, (4) every posterior half plus one midanterior half, and (5) alternative slices plus peripheral 3-mm rim of the remaining prostate.

RESULTS

Prostate cancers and their extraprostatic extension and resection margin involvement were commonly located in the right posterior portion of the prostate. Method 5 was most efficient, detecting all cases with extraprostatic extension and resection margin involvement and reducing 25% of paraffin blocks compared with the entire sampling of the prostate. The Gleason scores were retained in most of cases, except reversal of the primary and secondary Gleason grade component in only 2 cases (1%). Only 4 cases (3%) were downstaged within the same T2 stage.

CONCLUSIONS

These results demonstrate that sampling of alternative slices plus peripheral rim of the remaining prostate is the most efficient partial sampling method for radical prostatectomy specimens.

[Pathological interpretation of radical prostatectomy]

The examination by the pathologist of the whole prostate gland after radical prostatectomy allows close inspection of the tissue in order to determine the presence or absence of important prognostic pathological parameters, such as the histological grade, extracapsular extension, seminal vesicle invasion, positive surgical margins. Only complete embedding and multiple close steps sectioning of the whole prostate gland allows the more accurate assessment of the margin status. Specimens not sectioned from the whole organ carry the likelihood of missing important adverse pathologic features. The vast majority of departments of pathology in French institutions are used to study radical prostatectomy specimens obtained from the entire prostate gland.