Handling and reporting of radical prostatectomy specimens in Europe: a web-based survey by the European Network of Uropathology (ENUP)

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.

Accurate validation of ultrasound imaging of prostate cancer: a review of challenges in registration of imaging and histopathology

As the development of modalities for prostate cancer (PCa) imaging advances, the challenge of accurate registration between images and histopathologic ground truth becomes more pressing. Localization of PCa, rather than detection, requires a pixel-to-pixel validation of imaging based on histopathology after radical prostatectomy. Such a registration procedure is challenging for ultrasound modalities; not only the deformations of the prostate after resection have to be taken into account, but also the deformation due to the employed transrectal probe and the mismatch in orientation between imaging planes and pathology slices. In this work, we review the latest techniques to facilitate accurate validation of PCa localization in ultrasound imaging studies and extrapolate a general strategy for implementation of a registration procedure.

Intensity-based volumetric registration of magnetic resonance images and whole-mount sections of the prostate

OBJECTIVE

Magnetic Resonance Imaging (MRI) of the prostate provides useful in vivo diagnostic tissue information such as tumor location and aggressiveness, but ex vivo histopathology remains the ground truth. There are several challenges related to the registration of MRI to histopathology. We present a method for registration of standard clinical T2-weighted MRI (T2W-MRI) and transverse histopathology whole-mount (WM) sections of the prostate.

METHODS

An isotropic volume stack was created from the WM sections using 2D rigid and deformable registration combined with linear interpolation. The prostate was segmented manually from the T2W-MRI volume and registered to the WM section volume using a combination of affine and deformable registration. The method was evaluated on a set of 12 patients who had undergone radical prostatectomy. Registration accuracy was assessed using volume overlap (Dice Coefficient, DC) and landmark distances.

RESULTS

The DC was 0.94 for the whole prostate, 0.63 for the peripheral zone and 0.77 for the remaining gland. The landmark distances were on average 5.4 mm.

CONCLUSION

The volume overlap for the whole prostate and remaining gland, as well as the landmark distances indicate good registration accuracy for the proposed method, and shows that it can be highly useful for registering clinical available MRI and WM sections of the prostate.

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.

Variation between specialist uropatholgists in reporting extraprostatic extension after radical prostatectomy

Aims

Extraprostatic extension of prostate cancer in radical prostatectomy specimens significantly affects patient management. We evaluated the degree of interobserver variation between uropathologists at a tertiary referral teaching hospital in assessing the extraprostatic extension of prostate cancer in radical prostatectomy specimens.

Methods

Histopathological data from a consecutive series of 293 radical prostatectomy specimens (January 2007–December 2012) were reviewed. A subset of 50 consecutive radical prostatectomy cases originally staged as tumours confined to the prostate (pT2) or tumours extending into periprostatic tissue (pT3a) during this period were reviewed by four specialist uropathologists.

Results

Five consultant histopathologists reported these specimens with significant differences in the reported stage (p=0.0164) between pathologists. Double-blind review by 4 uropathologists of 50 consecutive radical prostatectomy cases showed a lack of consensus in 16/50 (32%) cases (κ score 0.58, moderate agreement). A consensus meeting was held, but consensus could still not be reached in 9/16 cases.

Conclusions

Our findings highlight variability in the reporting of pT stage in radical prostatectomy specimens even by specialist uropathologists. Assessment of extraprostatic extension has important implications for patient management and there is a need for more precise guidance.

Maximum tumor diameter adjusted to the risk profile predicts biochemical recurrence after radical prostatectomy

Currently, no consensus exists on the best method for tumor quantification in prostate cancer (PCA), and its prognostic value remains controversial. We evaluated how a newly defined maximum tumor diameter (MTD) might contribute to the prediction of biochemical recurrence (BCR) in a consecutive series of PCA patients treated with radical prostatectomy (RP). Patients with PCA who underwent RP without neoadjuvant therapy at a single center were included for analysis. MTD was defined as the largest diameter of all identified tumors in all three dimensions (i.e., length, width, or depth) of the prostate ("Basel technique"). Cox regression models addressed the association of MTD with BCR in three risk groups (low risk-prostate-specific antigen (PSA) < 10 ng/ml, pT2, and Gleason score (GS) ≤ 6; intermediate risk-PSA ≥ 10 and <20 ng/ml and/or pT2 and GS = 7; high risk-PSA > 20 ng/ml or pT3 or GS ≥ 8) and whole cohort. Within a median follow-up of 44 months (interquartile range (IQR) 23-66), 48 patients (9.4 %) in the intermediate-risk and high-risk groups experienced BCR. In multivariate Cox regression analysis, PSA, pathological stage (pT stage), GS, positive surgical margins (PSMs), and MTD > 19.5 mm were independent predictors for BCR (p < 0.05). In subgroup analysis, MTD as a nominal variable (<24.5 and >24.5 mm) was the only independent predictor of BCR in the intermediate-risk group (hazard ratio (HR) 9.933, 95 % confidence interval (CI) 2.070-47.665; p < 0.05). MTD is an independent risk factor of BCR in PC patients after RP. The combination of the MTD with other well-known prognostic factors after RP may improve decision-making concerning follow-up intensity or adjuvant treatment.

A Workflow to Improve the Alignment of Prostate Imaging with Whole-mount Histopathology

RATIONALE AND OBJECTIVES

Evaluation of prostate imaging tests against whole-mount histology specimens requires accurate alignment between radiologic and histologic data sets. Misalignment results in false-positive and -negative zones as assessed by imaging. We describe a workflow for three-dimensional alignment of prostate imaging data against whole-mount prostatectomy reference specimens and assess its performance against a standard workflow.

MATERIALS AND METHODS

Ethical approval was granted. Patients underwent motorized transrectal ultrasound (Prostate Histoscanning) to generate a three-dimensional image of the prostate before radical prostatectomy. The test workflow incorporated steps for axial alignment between imaging and histology, size adjustments following formalin fixation, and use of custom-made parallel cutters and digital caliper instruments. The control workflow comprised freehand cutting and assumed homogeneous block thicknesses at the same relative angles between pathology and imaging sections.

RESULTS

Thirty radical prostatectomy specimens were histologically and radiologically processed, either by an alignment-optimized workflow (n = 20) or a control workflow (n = 10). The optimized workflow generated tissue blocks of heterogeneous thicknesses but with no significant drifting in the cutting plane. The control workflow resulted in significantly nonparallel blocks, accurately matching only one out of four histology blocks to their respective imaging data. The image-to-histology alignment accuracy was 20% greater in the optimized workflow (P < .0001), with higher sensitivity (85% vs. 69%) and specificity (94% vs. 73%) for margin prediction in a 5 × 5-mm grid analysis.

CONCLUSIONS

A significantly better alignment was observed in the optimized workflow. Evaluation of prostate imaging biomarkers using whole-mount histology references should include a test-to-reference spatial alignment workflow.

DNA comparison between operative and biopsy specimens to investigate stage pT0 after radical prostatectomy

PURPOSE

The aim was to eliminate, by DNA comparison, any identity mismatch between operative and biopsy specimens and to analyse the determinants of all pT0 prostate cancers occurred in a single institution.

METHODS

All prostate pT0 cases in a single institution over 20 years were investigated. None of the patients had been diagnosed after a transurethral resection of the prostate nor had they received neoadjuvant hormonal treatment. The biopsies performed in other centres had been referred for a centralized pathologic re-analysis. DNA analysis was performed in samples from operative and biopsy specimens, and pairs of tissues were blindly constituted. Correct matching was verified in each pair and compared to the original database in order to comment on the occurrence of identity mismatches in the series.

RESULTS

Nineteen patients (0.77 %) had been diagnosed as having pT0 prostate cancer among the 2,462 RP procedures performed over 19 years. The biopsy re-analysis invalidated the initial diagnosis of prostate cancer in one biopsy set performed elsewhere. Among 12 entirely processed cases, the biochemistry procedure evaluated as "very unlikely" the occurrence of an error in tissue identification in the biopsy setting, during the surgical procedure or the pathological analysis. No identification error of tissue samples was established in this first verified pT0 series.

CONCLUSIONS

Although it must be suspected, specimen identification error was not a cause for pT0 prostate cancer. Only after a full pathological and DNA verification, the pT0 stage remains a sole entity, unexplained in most cases.

Standardization of Gleason grading among 337 European pathologists

AIMS

  The 2005 International Society of Urological Pathology (ISUP) modification of Gleason grading recommended that the highest grade should always be included in the Gleason score (GS) in prostate biopsies. We analysed the impact of this recommendation on reporting of GS 6 versus 7.

METHODS AND RESULTS

  Fifteen expert uropathologists reached two-thirds consensus on 15 prostate biopsies with GS 6-7 cancer. Eighty-five microphotographs were graded by 337 of 617 members of the European Network of Uropathology (ENUP), representing 19 countries. There was agreement between expert and majority member GS in 12 of 15 cases, while members upgraded in three cases. Among members and the expert consensus, a GS >6 was assigned by 64.5% and 60%, respectively. Mean member GS was higher than consensus GS in nine of 15 cases. A Gleason pattern (GP) 5 was reported by 0.3-5.6% in 10 cases. Agreement between consensus and member GS was 58.2-89.3% (mean 71.4%) in GS 6 cases and 46.3-63.8% (mean 56.4%) in GS 7 cases (P = 0.009).

CONCLUSIONS

  While undergrading of prostate cancer used to be prevalent, some now tend to overgrade. Minimum diagnostic criteria for GP 4 and 5 in biopsies need to be better defined. Image libraries reviewed by experts may be useful for standardization.

Whole-mount evaluation of penectomies for penile cancer: feasibility, cost and comparison to routine sectioning

AIMS

Pathological staging in penectomies may be difficult due to the anatomical complexity of penile anatomy, and may be additionally challenging due to the low volume at most institutions. Our study aimed to assess the feasibility of whole-mount processing for penectomy specimens.

METHODS AND RESULTS

A 7-year retrospective search for partial or radical penectomies identified 55 specimens, which were processed routinely (n = 31) from 2006 to 2009 and whole-mounted (n = 24) from 2010 to 2012. Routine cases used more slides per case compared to whole mounts (mean 10.4 versus 7.2). Recuts occurred more often in routine cases (12.9% versus 0%). More routine cases had additional blocks grossed (19.4% versus 4.2%). Upon review, five discrepancies that impacted pT staging were identified in the routine group, with none in the whole-mount group. The average estimated additional cost for each whole-mount case compared to routine processing was $40.74, with an increased turnaround time of 1 day.

CONCLUSIONS

Whole-mounting is a feasible technique for penectomy that can be utilized with minimal increased cost and turnaround time, and may improve staging. Institutions in which whole-mounting is already established for other organs, such as prostate, may wish to consider utilizing this format for penectomy specimens.

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.

[Status and medicolegal implications in France pT0 stage of prostate cancer: a study by the CC-AFU]

OBJECTIVE

To assess the frequency, circumstances, and possible medico-legal consequences of the pT0 prostate cancer, defined by the absence of tumor in a radical prostatectomy specimen.

METHODS

Six centers retrospectively identified all cases of pT0 and selectionned those that occurred without prior hormone therapy or prostate resection. Preoperative data, histological report and clinical and biological outcome were analyzed. The lawsuits' registry in pathology were consulted at insurance companies.

RESULTS

Thirty cases of pT0 prostate cancer (0.4%) were reported on 7693 patients. The median age was 63years, PSA 7.4ng/mL. The number of positive preoperative biopsies ranged from one to four for a median tumor length of 1mm (0.3 to 18mm). The biopsy Gleason score was 3+3 for 23 patients, less than 5 for six others and included a contingent of grade 4 in two patients. With a median follow-up of 82months, no clinical or biochemical recurrence was observed. One patient complaint for pT0 prostate was found in the insurances registry.

CONCLUSION

The occurrence of a prostate pT0 called into question all the diagnostic procedures and surgical indication. To avoid a forensic procedure, urologists should inform patients of the possibility of this situation before radical prostatectomy.

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.

International Society of Urological Pathology (ISUP) consensus conference on handling and staging of radical prostatectomy specimens: rationale and organization

The 2009 International Society of Urological Pathology consensus conference in Boston, made recommendations regarding the standardization of pathology reporting of radical prostatectomy specimens. The activities of the conference were coordinated through five workgroups. The results are presented in five separate reports covering (1) specimen handling, (2) T2 substaging and prostate cancer volume, (3) extraprostatic extension, lymphovascular invasion and locally advanced disease, (4) seminal vesicles and lymph node metastases and (5) surgical margins. In this introductory article we describe some novel features of the organization of the consensus process. Following the completion of a pre-meeting survey conference, participants discussed and voted on 43 specific issues of contention relating to the pathological reporting of radical prostatectomy specimens. Consensus, defined as agreement by at least 65% of participants present, was achieved for 30 questions.

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.

International Society of Urological Pathology (ISUP) Consensus Conference on Handling and Staging of Radical Prostatectomy Specimens. Working group 4: seminal vesicles and lymph nodes

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 infiltration of tumor into the seminal vesicles and regional lymph nodes were coordinated by working group 4. There was a consensus that complete blocking of the seminal vesicles was not necessary, although sampling of the junction of the seminal vesicles and prostate was mandatory. There was consensus that sampling of the vas deferens margins was not obligatory. There was also consensus that muscular wall invasion of the extraprostatic seminal vesicle only should be regarded as seminal vesicle invasion. Categorization into types of seminal vesicle spread was agreed by consensus to be not necessary. For examination of lymph nodes, there was consensus that special techniques such as frozen sectioning were of use only in high-risk cases. There was no consensus on the optimal sampling method for pelvic lymph node dissection specimens, although there was consensus that all lymph nodes should be completely blocked as a minimum. There was also a consensus that a count of the number of lymph nodes harvested should be attempted. In view of recent evidence, there was consensus that the diameter of the largest lymph node metastasis should be measured. These consensus decisions will hopefully clarify the difficult areas of pathological assessment in radical prostatectomy evaluation and improve the concordance of research series to allow more accurate assessment of patient prognosis.

Formalin fixation and immunoreactivity in prostate cancer and benign prostatic tissues

For better fixation, formalin injection of radical prostatectomy (RP) specimens has been suggested. We aimed to assess its effect on immunoreactivity using immunohistochemistry (IHC). A tissue microarray of cancer and benign tissues from 42 RP specimens was constructed. Twenty-one of the prostates had been injected with formalin prior to formalin immersion. IHC staining was performed using 15 antibodies, including nuclear and cytoplasmic markers known to be positive in prostate tissue: pan cytokeratin, P504S, high molecular weight (HMW) keratin, PSA, vimentin, actin HHF35, thioredoxin-1, peroxiredoxin-2, PDX-1, BAX, p27, androgen receptor (AR) and heat shock proteins (HSP) 27, 60 and 70. Differences in staining intensity in cancer and benign tissues were compared separately except for HMW keratin. Only 7 of 29 analyses showed significant differences between groups, including 5 of 15 antibodies. The expression of AR and HSP 27 was stronger in formalin-injected tissue, while the opposite was true for HSP 60, HSP 70 and peroxiredoxin-2. For most antibodies, formalin injection does not significantly affect immunoreactivity in prostate tissue. The staining variability caused by inter- and intratumoral heterogeneity may be greater than that caused by the fixation method.