Gleason scoring: a comparison of classical and modified (International Society of Urological Pathology) criteria using nadir PSA as a clinical end point

Prognostic Utility of the Gleason Grading System Revisions and Histopathological Factors Beyond Gleason Grade

Background

The International Society of Urological Pathology (ISUP) revised the Gleason system in 2005 and 2014. The impact of these changes on prostate cancer (PCa) prognostication remains unclear.

Objective

To evaluate if the ISUP 2014 Gleason score (GS) predicts PCa death better than the pre-2005 GS, and if additional histopathological information can further improve PCa death prediction.

Patients and Methods

We conducted a case–control study nested among men in the National Prostate Cancer Register of Sweden diagnosed with non-metastatic PCa 1998–2015. We included 369 men who died from PCa (cases) and 369 men who did not (controls). Two uro-pathologists centrally re-reviewed biopsy ISUP 2014 Gleason grading, poorly formed glands, cribriform pattern, comedonecrosis, perineural invasion, intraductal, ductal and mucinous carcinoma, percentage Gleason 4, inflammation, high-grade prostatic intraepithelial neoplasia (HGPIN) and post-atrophic hyperplasia. Pre-2005 GS was back-transformed using i) information on cribriform pattern and/or poorly formed glands and ii) the diagnostic GS from the registry. Models were developed using Firth logistic regression and compared in terms of discrimination (AUC).

Results

The ISUP 2014 GS (AUC = 0.808) performed better than the pre-2005 GS when back-transformed using only cribriform pattern (AUC = 0.785) or both cribriform and poorly formed glands (AUC = 0.792), but not when back-transformed using only poorly formed glands (AUC = 0.800). Similarly, the ISUP 2014 GS performed better than the diagnostic GS (AUC = 0.808 vs 0.781). Comedonecrosis (AUC = 0.811), HGPIN (AUC = 0.810) and number of cores with ≥50% cancer (AUC = 0.810) predicted PCa death independently of the ISUP 2014 GS.

Conclusion

The Gleason Grading revisions have improved PCa death prediction, likely due to classifying cribriform patterns, rather than poorly formed glands, as Gleason 4. Comedonecrosis, HGPIN and number of cores with ≥50% cancer further improve PCa death discrimination slightly.

Temporal changes in cause-specific death in men with localised prostate cancer treated with radical prostatectomy: a population-based, nationwide study

Background and Objective

Changes in diagnostic work‐up, histopathological assessment, and treatment of men with prostate cancer during the last 20 years have affected the prognosis. The objective was to investigate the risk of prostate cancer death in men with clinically localised prostate cancer treated with radical prostatectomy in Sweden in 2000–2010.

Methods

Population‐based, nationwide, study on men with clinically localised prostate cancer treated with radical prostatectomy in the period 2000–2010. Cox regression analyses were used to assess differences in risk of prostate cancer death according to calendar period for diagnosis and stratified on risk category.

Results

The study included 19 330 men with a median follow‐up of 12.4 years. Men diagnosed in 2007–2008 and 2009–2010 had a significantly lower risk of prostate cancer death compared to men diagnosed in 2000–2002. The reduced risk of prostate cancer death was restricted to men with intermediate‐risk prostate cancer with no differences observed in men with low‐ or high‐risk prostate cancer.

Conclusion

During the study period, the risk of prostate cancer death decreased in the total population of men with localised prostate cancer treated with radical prostatectomy. The decrease was restricted to men with intermediate‐risk prostate cancer.

Prognostic features of Annexin A2 expression in prostate cancer

ANXA2 (Annexin A2 or Annexin II) is a calcium dependent phospholipid binding protein with diverse cellular functions. While ANXA2 is either absent or expressed focally in the prostate epithelium of well and moderately differentiated tumours, it is highly expressed in a subset of poorly differentiated tumours. Here we examined the association between ANXA2 expression and tumour progression, with consideration of ERG expression status and patient race (Caucasian American and African American). We evaluated ANXA2 and ERG expression in index tumours by immunohistochemistry of whole mounted prostate sections and tissue microarrays derived from radical prostatectomies of 176 patients, matched for long term post-radical prostatectomy follow-up of up to 22 years (median 12.6 years), race and pathological stage. Expression of ERG and ANXA2 was analysed for correlation with grade group (GG), and pathological T (pT) stage. Kaplan-Meier estimation curves were used to examine associations between ANXA2 or ERG expression and biochemical recurrence (BCR) free survival, and distant metastasis free survival. Significant associations were found between ANXA2(+) index tumours and poorest grade groups (GG 4-5, p=0.0037), and worse pathological stage (pT 3-4, p=0.0142). Patients with ANXA2(+) prostate tumours showed trends towards earlier BCR and metastatic progression. ANXA2(+)/ERG(-) tumours were found to be associated with GG 4-5; ANXA2(-)/ERG(+) tumours, with GG 1-2 (p=0.0036). ANXA2 expression was not associated with patient race. The association between high ANXA2 expression and prostate tumours of higher grade (GG 4-5) and stage (pT 3-4) suggests a potential use for ANXA2 as a prognostic biomarker of aggressive prostate cancer.

Influence of African American race on the association between preoperative biopsy grade group and adverse histopathologic features of radical prostatectomy

BACKGROUND

The current study was performed to evaluate the influence of race on the association between biopsy grade group (GrGp) and the risk of detectable prostate-specific antigen (PSA) and adverse histopathological outcomes after radical prostatectomy (RP).

METHODS

Data regarding 4073 men (1344 African American men; 33%) who were treated with RP were categorized based on the 5-tiered GrGp system. Logistic regression was used to test the association between biopsy GrGp and PSA nadir (<0.1 ng/mL) after RP as well as adverse pathological features among all patients and stratified by race.

RESULTS

Those patients with a higher biopsy GrGp were found to have lower odds of achieving a PSA nadir <0.1 ng/mL after RP on unadjusted and multivariable analysis (both P < .001). On unadjusted and multivariable analysis, higher GrGp was associated with increased odds of each of the adverse pathological features, namely, GrGp ≥3, extraprostatic extension, seminal vesicle invasion, positive surgical resection margin, and positive lymph nodes (all P < .001). Race had no significant interaction with biopsy GrGp in the prediction of PSA nadir after RP (P = .91) or any adverse pathological features (all P > .06) except positive lymph nodes. When the models were stratified by race, the associations between preoperative biopsy GrGp and having a PSA nadir <0.1 ng/mL, high-grade final pathology, or other adverse histopathologic features were similar in both races except as noted for positive lymph nodes.

CONCLUSIONS

Higher preoperative biopsy GrGp is associated with increased odds of adverse histopathological findings as well as lower odds of a PSA nadir <0.1 ng/mL after RP. These associations are largely independent of race, suggesting that GrGp is an accurate tool for risk stratification in both black and white men.

Stiffness of prostate gland measured by transrectal real-time shear wave elastography for detection of prostate cancer: a feasibility study

OBJECTIVE

This study aimed to evaluate the value of the Young's modulus obtained by transrectal real-time shear wave elastography (SWE) for detection of prostate cancer (PCa).

METHODS

215 patients underwent SWE in six identical planes before biopsy guided with transrectal ultrasonography. The Young's modulus of the entire prostate gland was defined as the mean of the results in these planes. The measurements were compared with the pathological results, the prostate specific antigen (PSA), and the Gleason score (GS) after biopsy.

RESULTS

The Young's modulus of elasticity, including the maximum Young's modulus (Emax), the mean Young's modulus (Emean), and the minimum Young's modulus (Emin), were significantly higher in malignant lesions than those in benign lesions (all p < 0.05). The optimal cut-off values for PCa were 128.48 kPa, 62.27 kPa, and 20.03 kPa, respectively. The sensitivities were 77.88%, 81.42%, and 60.18%, respectively, and the specificities were 85.33%, 74.51 and 63.73 %, respectively. PSA positively correlated with Emax and Emean (r = 0.686 and 0.678, respectively), as did the GS (r = 0.410 and 0.382, respectively).

CONCLUSION

The Young's modulus of entire prostate gland can be used to differentiate benign from malignant prostatic lesions. There were higher Young's modulus of elasticity and higher risk of malignant lesions. Meanwhile, higher Young's modulus correlated with higher PSA and GS.

ADVANCES IN KNOWLEDGE

This study indicates SWE can detect PCa by quantified the stiffness of entire prostate gland whether the lesions have been visible or not on gray-scale and Doppler ultrasound.

Grading of prostate cancer: a work in progress

Grading of prostate cancer has evolved substantially over time, not least because of major changes in diagnostic approach and concomitant shifts from late- to early-stage detection since the adoption of PSA testing from the late 1980s. After the conception of the architecture-based nine-tier Gleason grading system more than 50 years ago, several changes were made in order to increase its prognostic impact, to reduce interobserver variation and to improve concordance between prostate needle biopsy and radical prostatectomy grading. This eventually resulted in the current five-tier grading system, with a much more detailed description of the individual architectural patterns constituting the remaining three Gleason patterns (i.e. grades 3-5). Nevertheless, there is room for improvement. For instance, distinction of common grade 4 subpatterns such as ill-formed and fused glands from the grade 3 pattern is challenging, blurring the division between low-risk patients who could be eligible for deferred therapy and those who need curative therapy. The last few years have witnessed the publication of several studies on the prognostic impact of individual architectural subpatterns showing that, in particular, the cribriform pattern exceeded the prognostic impact of other grade 4 subpatterns. This review provides an overview of the changes in prostate cancer grading over time and provides a thorough description of the various Gleason subpatterns, the current evidence of their prognostic impact and areas of contention. Potential practical ways for improvements of the current grading system are also put forward.

Clinical significance of subtypes of Gleason pattern 4 prostate cancer

Major updates in prostate cancer grading have been adopted in recent times. These include redefinitions of Gleason pattern (GP) 4 architectural variants and reporting of the grade group (GG) system, which divides prostate cancer into five groups that better stratify patients. Still, the GG system uses the GPs 3, 4 or 5 to define each GG. Patients belonging to GG 2, 3 and 4 have increasing amounts of GP 4 in the composition of their tumors. GP4 is a heterogeneous group of morphologic variants that include poorly formed glands, glomeruloid structures, cribriform glands, and fused glands. Recently published studies suggest that the morphologic subtypes of GP 4 have different clinical significance. While the diagnostic reproducibility of poorly formed glands and fused glands is low, glomeruloid structures and cribriform glands are easier to be distinguished from other morphologies. A growing body of evidence suggests that the presence of cribriform glands is associated with an aggressive clinical course compared with other architectural subtypes. The latest 2014 guidelines issued by the International Society of Urologic Pathology recommend that the percentage of GP 4 be reported on needle biopsies and radical prostatectomy (RP) specimens. The data reviewed here invites consideration for the need to report the subtype of GP 4, especially the presence or absence of cribriform glands.

The present and future of prostate cancer histopathology

PURPOSE OF REVIEW

The present review describes recent changes in the histologic grading of prostatic adenocarcinoma and emerging data suggesting areas for further grade optimization.

RECENT FINDINGS

The grading of prostatic adenocarcinoma has evolved over time, and optimization for active surveillance management has been one major driving force. Recent changes include adoption of the Grade Group system, which stratifies patients into one of five prognostic groups. Although it provides clearer labels for patient understanding and defines a more homogenous low-risk group (i.e. Grade Group 1 of 5), emerging data suggest that further prognostic stratification may be achieved by incorporating other histologic findings. The impact of 'cribriform histology' and intraductal carcinoma as aggressive features of prostate cancer has gained significant recognition. Furthermore, quantifying the fraction of each individual Gleason pattern component may also add prognostic stratification. In addition to Gleason score and Grade Group, some institutions now identify and report high-risk histologic patterns (e.g. 'cribriform histology') and the percentage of Gleason pattern 4 on biopsies. While early in adoption, these additional features are being used to further stratify patients beyond the Grade Group system, particularly for patients with Grade Group 2 carcinomas. These histologic findings will likely be incorporated into future modifications of the grading system to further optimize patient stratification and ensure reporting consistency.

SUMMARY

The histologic evaluation of prostatic adenocarcinoma provides strong prognostic information for clinical management. The recent Grade Group system offers many improvements, but further optimization based on specific histologic patterns may evolve.

Prostatectomy-based validation of combined urine and plasma test for predicting high grade prostate cancer

BACKGROUND

Distinguishing between low- and high-grade prostate cancers (PCa) is important, but biopsy may underestimate the actual grade of cancer. We have previously shown that urine/plasma-based prostate-specific biomarkers can predict high grade PCa. Our objective was to determine the accuracy of a test using cell-free RNA levels of biomarkers in predicting prostatectomy results.

METHODS

This multicenter community-based prospective study was conducted using urine/blood samples collected from 306 patients. All recruited patients were treatment-naïve, without metastases, and had been biopsied, designated a Gleason Score (GS) based on biopsy, and assigned to prostatectomy prior to participation in the study. The primary outcome measure was the urine/plasma test accuracy in predicting high grade PCa on prostatectomy compared with biopsy findings. Sensitivity and specificity were calculated using standard formulas, while comparisons between groups were performed using the Wilcoxon Rank Sum, Kruskal-Wallis, Chi-Square, and Fisher's exact test.

RESULTS

GS as assigned by standard 10-12 core biopsies was 3 + 3 in 90 (29.4%), 3 + 4 in 122 (39.8%), 4 + 3 in 50 (16.3%), and > 4 + 3 in 44 (14.4%) patients. The urine/plasma assay confirmed a previous validation and was highly accurate in predicting the presence of high-grade PCa (Gleason ≥3 + 4) with sensitivity between 88% and 95% as verified by prostatectomy findings. GS was upgraded after prostatectomy in 27% of patients and downgraded in 12% of patients.

CONCLUSIONS

This plasma/urine biomarker test accurately predicts high grade cancer as determined by prostatectomy with a sensitivity at 92-97%, while the sensitivity of core biopsies was 78%.

Validation of the WHO 2016 new Gleason score of prostatic carcinoma

Context

New Gleason Score of Prostate.

Aims

The aim of this study is to assign the patients with carcinoma prostate into new prognostic grade groups (PGGs) based on revised Gleason score (GS) and follow-up according to the WHO 2016.

Subjects and Methods

All the biopsies/resected specimens of carcinoma prostate from January 2014 to June 2016 were reviewed, and GS was done according to the WHO 2016. Accordingly, cribriform, fused, and glomeruloid glands were assigned GS 4. Thus, two groups were identified with GS 7 (3 + 4 and 4 + 3). The patients were grouped into PGGs 1-5. The number of patients with change in the prognostic group along with follow-up was calculated.

Results

There were 143 patients with carcinoma prostate, with a median age of 65 years. The initial GS was revised, and there was a decrease in GS 3 + 4 from 13.9% to 9% and increase in 4 + 3 from 19.6% to 23.8%. There was upgradation of PGG in 11 (7.69%) biopsies; with PGG from 1 to 2 in one; 2to 3 in eight; and 3to 4 in two. Follow-up at 2 years in 22 showed the poor prognoses in the patients who were upgraded to the higher prognostic group.

Conclusions

A change in PGG according to the WHO 2016 criteria was assigned in 7.69% biopsies of carcinoma prostate, and it correlated with prognosis.

The prognostic significance of the 2014 International Society of Urological Pathology (ISUP) grading system for prostate cancer

The 2005 International Society of Urological Pathology (ISUP) modified Gleason grading system was further amended in 2014 with the establishment of grade groupings (ISUP grading). This study examined the predictive value of ISUP grading, comparing results with recognised prognostic parameters.Of 3700 men undergoing radical prostatectomy (RP) reported at Aquesta Pathology between 2008 and 2013, 2079 also had a positive needle biopsy available for review. We examined the association between needle biopsy 2014 ISUP grade and 2005 modified Gleason score, tumour volume, pathological stage of the subsequent RP tumour, as well as biochemical recurrence-free survival (BRFS). The median age was 62 (range 32-79 years). Median serum prostate specific antigen was 5.9 (range 0.4-69 ng/mL). For needle biopsies, 280 (13.5%), 1031 (49.6%), 366 (17.6%), 77 (3.7%) and 325 (15.6%) were 2014 ISUP grades 1-5, respectively. Needle biopsy 2014 ISUP grade showed a significant association with RP tumour volume (p < 0.001), TNM pT and N stage (p < 0.001) and BRFS (p < 0.001). Multivariate analysis using Cox proportional hazards regression model showed serum prostate specific antigen (PSA) at the time of diagnosis and ISUP grade >2 to be significantly associated with BRFS.This study provides evidence of the prognostic significance of ISUP grading for thin core needle biopsy of prostate.

Validation of International Society of Urological Pathology (ISUP) grading for prostatic adenocarcinoma in thin core biopsies using TROG 03.04 'RADAR' trial clinical data

In 2014 a consensus conference convened by the International Society of Urological Pathology (ISUP) adopted amendments to the criteria for Gleason grading and scoring (GS) for prostatic adenocarcinoma. The meeting defined a modified grading system based on 5 grading categories (grade 1, GS 3+3; grade 2, GS 3+4; grade 3, GS 4+3; grade 4, GS 8; grade 5, GS 9-10). In this study we have evaluated the prognostic significance of ISUP grading in 496 patients enrolled in the TROG 03.04 RADAR Trial. There were 19 grade 1, 118 grade 2, 193 grade 3, 88 grade 4 and 79 grade 5 tumours in the series, with follow-up for a minimum of 6.5 years. On follow-up 76 patients experienced distant progression of disease, 171 prostate specific antigen (PSA) progression and 39 prostate cancer deaths. In contrast to the 2005 modified Gleason system (MGS), the hazards of the distant and PSA progression endpoints, relative to grade 2, were significantly greater for grades 3, 4 and 5 of the 2014 ISUP grading scheme. Comparison of predictive ability utilising Harrell's concordance index, showed 2014 ISUP grading to significantly out-perform 2005 MGS grading for each of the three clinical endpoints.

From Gleason to International Society of Urological Pathology (ISUP) grading of prostate cancer

Gleason grading of prostate cancer has gained worldwide acceptance since its introduction 50 years ago. This system has fulfilled the role of a powerful prognostic indicator for many years and this has influenced treatment. There have been numerous changes to the management and diagnosis of prostate cancer since 1966, including prostate-specific antigen screening, resulting in the early detection of prostate cancer, This has resulted in the evolution of Gleason grading with the informal adoption of a number of alterations. Significant changes to Gleason grading were made in 2005 through a consensus conference convened by the International Society of Urological Pathology (ISUP). In more recent times, the necessity for further changes to prostate cancer grading has been apparent and a follow-up ISUP consensus conference was held in 2014. Changes resulting from this conference included the classifying of all cribriform cancer and glomeruloid patterns as Gleason grade 4, the grading of mucinous adenocarcinoma based on underlying architecture rather than uniformly considering these tumors as pattern 4, and the introduction of a Gleason score (GS)-based 5 grade system, which incorporated the 2014 modifications to the Gleason grading system. Designated ISUP grade, this system consists of five grades: grade 1 (GS ≤3 + 3), grade 2 (GS 3 + 4), grade 3 (GS 4 + 3), grade 4 (GS 4 + 4, 3 + 5, 5 + 3) and grade 5 (GS 9-10). With further advances recently reported in the literature, it is apparent that amendments to the current system are likely to be necessary in the future.

Gleason and Fuhrman no longer make the grade

Grading is an important prognostic parameter for prostate adenocarcinoma and renal cell carcinoma (RCC); however, the most frequently used classifications fail to account for advances in our understanding of the diagnostic features, classification and/or behaviour of these tumours. In 2005 and 2014, the International Society of Urological Pathology (ISUP) proposed changes to Gleason scoring with the adoption of the ISUP grading for prostate cancer in 2014 (grade 1, score 3 + 3; grade 2, score 3 + 4; grade 3, score 4 + 3; grade 4, score 8; grade 5, score 9-10). Internationally the Fuhrman grading system is widely employed despite criticisms related to its application, validity, and reproducibility. In 2012, the ISUP established a grading system for RCC (grade 1, the nucleolus is not seen or is inconspicuous and basophilic at ×400 magnification; grade 2, nucleoli are eosinophilic and clearly visible at ×400 magnification; grade 3, nucleoli are clearly visible at ×100 magnification; grade 4, tumours show extreme pleomorphism or rhabdoid and/or sarcomatoid morphology). This grading has been validated for clear cell RCC and papillary RCC. It was further recommended that chromophobe RCC not be graded. For other morphotypes of RCC, ISUP grading has not been validated as a prognostic parameter, but can be used for descriptive purposes.

The evolving Gleason grading system

The Gleason grading system for prostate adenocarcinoma has evolved from its original scheme established in the 1960s-1970s, to a significantly modified system after two major consensus meetings conducted by the International Society of Urologic Pathology (ISUP) in 2005 and 2014, respectively. The Gleason grading system has been incorporated into the WHO classification of prostate cancer, the AJCC/UICC staging system, and the NCCN guidelines as one of the key factors in treatment decision. Both pathologists and clinicians need to fully understand the principles and practice of this grading system. We here briefly review the historical aspects of the original scheme and the recent developments of Gleason grading system, focusing on major changes over the years that resulted in the modern Gleason grading system, which has led to a new "Grade Group" system proposed by the 2014 ISUP consensus, and adopted by the 2016 WHO classification of tumours of the prostate.

Diagnosis of "Poorly Formed Glands" Gleason Pattern 4 Prostatic Adenocarcinoma on Needle Biopsy: An Interobserver Reproducibility Study Among Urologic Pathologists With Recommendations

Accurate recognition of Gleason pattern (GP) 4 prostate carcinoma (PCa) on needle biopsy is critical for patient management and prognostication. "Poorly formed glands" are the most common GP4 subpattern. We studied the diagnostic reproducibility and the quantitative threshold of grading GP4 "poorly formed glands" and the criteria to distinguish them from tangentially sectioned GP3 glands. Seventeen urologic pathologists were first queried for the definition of "poorly formed glands" using cases representing a spectrum of PCa glandular differentiation. Cancer glands with no or rare lumens, elongated compressed glands, and elongated nests were considered "poorly formed glands" by consensus. Participants then graded a second set of 23 PCa cases that potentially contained "poorly formed glands" with a fair interobserver agreement (κ = 0.34). The consensus diagnoses, defined as agreement by > 70% participants, were then correlated with the quantitative (≤ 5, 6 to 10, >10) and topographic features of poorly formed glands (clustered, immediately adjacent to, and intermixed with other well-formed PCa glands) in each case. Poorly formed glands immediately adjacent to other well-formed glands regardless of their number and small foci of ≤ 5 poorly formed glands regardless of their location were not graded as GP4. In contrast, large foci of >10 poorly formed glands that were not immediately adjacent to well-formed glands were graded as GP4. Grading "poorly formed glands" is challenging. Some morphologic features are, however, reproducible for and against a GP4 diagnosis. This study represents an important step in standardization of grading of "poorly formed glands" based on quantitative and topographic morphologic features.

Gleason inflation 1998-2011: a registry study of 97,168 men

OBJECTIVES

To study long-term trends in Gleason grading in a nationwide population and to assess the impact of the International Society of Urological Pathology (ISUP) revision in 2005 of the Gleason system on grading practices, as in recent years there has been a shift upwards in Gleason grading of prostate cancer.

PATIENTS AND METHODS

All newly diagnosed prostate cancers in Sweden are reported to the National Prostate Cancer Register (NPCR). In 97 168 men with a primary diagnosis of prostate cancer on needle biopsy from 1998 to 2011, Gleason score, clinical T stage (cT) and serum levels of prostate-specific antigen (s-PSA) at diagnosis were analysed.

RESULTS

Gleason score, cT stage and s-PSA were reported to the NPCR in 97%, 99% and 99% of cases. Before and after 2005, Gleason score 7-10 was diagnosed in 52% and 57%, respectively (P < 0.001). After standardisation for cT stage and s-PSA with 1998 as baseline these tumours increased from 59% to 72%. Among low-risk tumours (stage cT1 and s-PSA 4-10 ng/mL) Gleason score 7-10 increased from 16% in 1998 to 40% in 2011 (P trend < 0.001), mean 19% and 33% before and after 2005 (P < 0.001). Among high-risk tumours (stage T3 and s-PSA 20-50 ng/mL) Gleason score 7-10 increased from 65% in 1998 to 94% in 2011 (P trend < 0.001), mean 78% and 90% before and after 2005 (P < 0.001). A Gleason score of 2-5 was reported in 27% in 1998 and 1% in 2011. Gleason score 5 decreased sharply after 2005 and Gleason score 2-4 was almost abandoned.

CONCLUSIONS

There has been a gradual shift towards higher Gleason grading, which started before 2005 but became more evident after the ISUP 2005 revision. Among low-stage tumours reporting of Gleason score 7-10 was more than doubled during the study period. When corrected for stage migration upgrading is considerable over recent decades. This has clinical consequences for therapy decisions such as eligibility for active surveillance. Grading systems need to be as stable as possible to enable comparisons over time and to facilitate the interpretation of the prognostic impact of grade.

Gleason drift in the NIHR ProtecT study

AIMS

There is increasing evidence of Gleason score (GS) drift in prostatic core biopsies during the last two decades. The ProtecT study is a randomized controlled study and provides an excellent cohort to study the effect of time, prostate-specific antigen (PSA) level, perineural invasion, tumour length and age on GS.

METHODS AND RESULTS

The ProtecT study recruited men in the United Kingdom between 1999 and 2010. The Gleason scores were grouped into four categories ≤ 3 + 3, 3 + 4, 4 + 3 and ≥ 4 + 4 for analysis. Data from England between 2000 and 2012 were also available. A total of 3282 biopsies containing cancer were analysed. For each year of the ProtecT study, the odds of being diagnosed with a higher GS category increased by 4.9%. Higher GS was also associated with perineural invasion, increasing tumour length, age and PSA level. While biopsy GS from England was incomplete, it also showed a marked decrease in GS five and six tumours during the same period.

CONCLUSION

There was GS drift from 3 + 3 to 3 + 4 with time in the ProtecT study, but there appeared to be no significant change in percentage of GS 4 + 3 or higher. This drift was less dramatic when compared to GS in the rest of England.

Does cumulative prostate cancer length (CCL) in prostate biopsies improve prediction of clinically insignificant cancer at radical prostatectomy in patients eligible for active surveillance?

OBJECTIVES

To evaluate if cumulative prostate cancer length (CCL) on prostate needle biopsy divided by the number of biopsy cores (CCL/core) could improve prediction of insignificant cancer on radical prostatectomy (RP) in patients with prostate cancer eligible for active surveillance (AS).

PATIENTS AND METHODS

Patients diagnosed with prostate cancer on extended (≥10 cores) biopsy with an initial prostate-specific antigen (iPSA) level of <15 ng/mL, clinical stage (cT) ≤ 2a, and highest biopsy Gleason score 3 + 3 = 6 or 3 + 4 = 7 with <3 positive cores who underwent RP were included in the study. The CCL/core and presence of insignificant cancer (organ-confined, volume <0.5 mL, Gleason score at RP ≤6) were recorded. pT2 prostate cancer with RP Gleason score ≤3 + 4 = 7 and volume <0.5 mL were categorised as low-tumour-volume organ-confined disease (LV-OCD).

RESULTS

In all, 221 patients met the inclusion criteria: the mean age was 59 years and the median iPSA level was 4.5 ng/mL. The clinical stage was cT1 in 86% of patients; biopsy Gleason score was 3 + 3 = 6 in 67% (group 1) and 3 + 4 = 7 in 33% of patients (group 2). The maximum percentage of biopsy core involvement was <50 in 85%; the median CCL/core was 0.15 mm. Insignificant cancer was found in 27% and LV-OCD in 44% of patients. Group 2 was associated with higher number of positive cores, maximum percentage core involvement, total prostate cancer length, and CCL/core. Group 1 was more likely to have insignificant cancer (39%) or LV-OCD (54%) than group 2 (3% and 23%, respectively). Group 2 had significantly higher RP Gleason score and pathological stage. Univariate analysis of group 1 showed that the iPSA level, maximum percentage core involvement, prostate cancer length, and CCL/core were all significantly associated with insignificant cancer and LV-OCD. For group 2, the number of positive cores (1 vs 2) was also significantly associated with LV-OCD. On multivariate logistic regression analysis, maximum percentage core involvement of <50, and number of positive cores (1 vs 2) were independent predictors of insignificant cancer in group 1; biopsy Gleason score, maximum percentage core involvement of <50 and prostate cancer length of <3 mm or CCL/core of <0.2 mm were all independent predictors of LV-OCD in the whole population. The maximum percentage of core involvement of <50 and prostate cancer length of <3 mm or CCL/core of <0.2 mm were also independent predictors of LV-OCD in group 1 patients.

CONCLUSION

In patients eligible for AS, a CCL/core of <0.20 mm was significantly associated with insignificant cancer and LV-OCD. However, when parameters of cancer burden were considered, CCL/core did not independently add any additional value for predicting insignificant cancer in patients with biopsy Gleason score 6. The CCL/core was an independent predictor of LV-OCD in the whole population and in group 1 patients, although the model including prostate cancer length showed slightly higher area under the receiver operating characteristic curve.

The critical role of the pathologist in determining eligibility for active surveillance as a management option in patients with prostate cancer: consensus statement with recommendations supported by the College of American Pathologists, International Society of Urological Pathology, Association of Directors of Anatomic and Surgical Pathology, the New Zealand Society of Pathologists, and the Prostate Cancer Foundation

CONTEXT

Prostate cancer remains a significant public health problem. Recent publications of randomized trials and the US Preventive Services Task Force recommendations have drawn attention to overtreatment of localized, low-risk prostate cancer. Active surveillance, in which patients undergo regular visits with serum prostate-specific antigen tests and repeat prostate biopsies, rather than aggressive treatment with curative intent, may address overtreatment of low-risk prostate cancer. It is apparent that a greater awareness of the critical role of pathologists in determining eligibility for active surveillance is needed.

OBJECTIVES

To review the state of current knowledge about the role of active surveillance in the management of prostate cancer and to provide a multidisciplinary report focusing on pathologic parameters important to the successful identification of patients likely to succeed with active surveillance, to determine the role of molecular tests in increasing the safety of active surveillance, and to provide future directions.

DESIGN

Systematic review of literature on active surveillance for low-risk prostate cancer, pathologic parameters important for appropriate stratification, and issues regarding interobserver reproducibility. Expert panels were created to delineate the fundamental questions confronting the clinical and pathologic aspects of management of men on active surveillance.

RESULTS

Expert panelists identified pathologic parameters important for management and the related diagnostic and reporting issues. Consensus recommendations were generated where appropriate.

CONCLUSIONS

Active surveillance is an important management option for men with low-risk prostate cancer. Vital to this process is the critical role pathologic parameters have in identifying appropriate candidates for active surveillance. These findings need to be reproducible and consistently reported by surgical pathologists with accurate pathology reporting.

Upgrading and upstaging in prostate cancer: From prostate biopsy to radical prostatectomy

Prostate cancer (CaP) is the most common malignancy in men and the second cause of cancer-related mortality after lung cancer. Several studies have evaluated the correlation between bioptic and pathological Gleason score (GS), documenting a correlation ranging between 30 and 60%. The aim of this study was the evaluation of the association between bioptic and pathological GS in a series of patients undergoing prostate needle biopsy and subsequent radical prostatectomy. We also aimed to evaluate the possible prognostic factors of upgrading and upstaging. We prospectively collected and retrospectively reviewed data from 300 consecutive patients who underwent radical retropubic or robot-assisted prostatectomy at our Institution. Patients who underwent prostate needle biopsy, transrectal or transperineal, with a minimum of 5 samples, were included in this study. Upgrading and downgrading were defined as increase or decrease, respectively, from one prognostic grade group to another, similar to up- or downstaging. The mean age of the patients was 62.97 years and the mean prostate-spesific antigen (PSA) level was 7.83 ng/ml. A total of 51.3% of the population underwent a transperineal prostate biopsy. The most frequently represented bioptic GS was 3+3 (64.0%) followed by 3+4=7 (15.6%); the most frequent pathological Gleason score was 3+4 (44.3%), followed by 3+3 (31.0%). With reagard to the bioptic GS 4-5-6 group, approximately half of the specimens (46.7%) were subsequently upgraded to GS 3+4, and 5.3% to 4+3. With regards to the bioptic GS 3+4 group, 57.4% was confirmed in the surgical specimen. In the 4+3 group, 23.5% of the cases was downgraded to 3+4 and 35.3% was confirmed. With regards to stage, ~39.7% of the patients received an upstaging on the pathological specimen. We evaluated the correlations between preoperative serum PSA level, prostate volume, digital rectal examination and biopsy type and none of the variables considered exhibited a correlation with any upgrading (P>0.05). Moreover, we evaluated the correlations between the aforementioned variables and upstaging and, at the multivariate analysis, only a serum PSA <4 ng/ml was found to be an independent variable predictive of upstaging (P=0.017). Therefore, new tools are required to predict upgrading and upstaging of our patients, in order to ensure better counseling for optimal treatment planning.

The reasons behind variation in Gleason grading of prostatic biopsies: areas of agreement and misconception among 266 European pathologists

AIMS

The Gleason scoring system underwent revision at the International Society of Urological Pathology (ISUP) conference in 2005. It is not known how uropathologists have interpreted its recommendations.

METHOD AND RESULTS

A web-based survey to European Network of Uropathology members received replies from 266 pathologists in 22 countries. Eighty-nine per cent claimed to follow ISUP recommendations. Key areas of disagreement included the following. Smoothly rounded cribriform glands were assigned Gleason pattern (GP) 3 by 51% and GP 4 by 49%. Necrosis was diagnosed as GP 5 by 62%. Any amount of secondary pattern of higher grade in needle biopsies was included in the Gleason score by 58%. Tertiary GP of higher grade on needle biopsies was included in the Gleason score by only 58%. If biopsy cores were embedded separately, only 56% would give a Gleason score for each core/slide examined; 68% would give a concluding Gleason score and the most common method was a global Gleason score (77%). Among those who blocked multiple biopsy cores together, 46% would only give an overall Gleason score for the case.

CONCLUSION

Misinterpretation of ISUP 2005 is widespread, and may explain the variation in Gleason scoring seen. Clarity and uniformity in teaching ISUP 2005 recommendations is necessary.

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.

The effect of dutasteride on the detection of prostate cancer: A set of meta-analyses

BACKGROUND

Dutasteride has been shown to significantly improve symptoms of benign prostatic hyperplasia (BPH) and reduce clinical progression. Recent data from studies evaluating 5-alpha reductase inhibitors (5-ARIs) for the prevention of prostate cancer, however, suggest 5ARIs, including dutasteride, may be associated with increased incidence of Gleason 8-10 prostate tumours. This meta-analysis was undertaken to quantify the effect of dutasteride on detection of prostate cancer and high-grade prostate cancer.

METHODS

Our meta-analysis includes data from GlaxoSmithKline-sponsored phase III randomized clinical trials (with a study duration of ≥2 years) evaluating the effect of dutasteride, alone or in combination with tamsulosin, to treat BPH or to reduce the risk of prostate cancer. The incidence of prostate cancer, including Gleason 7-10 and Gleason 8-10, for patients taking either dutasteride, dutasteride plus tamsulosin, tamsulosin alone, or placebo, were evaluated using the Mantel-Haenszel Risk Ratio (MHRR) method of conducting meta-analyses.

RESULTS

The meta-analysis demonstrated that in a population with symptomatic BPH and/or at increased risk of prostate cancer, a statistically significant lower number of detectable prostate cancers was found in men taking dutasteride compared to control groups (MHRR: 0.66, 95% CI 0.52-0.85). In our analysis, there was no increased risk for Gleason 7-10 (MHRR: 0.83, 95% CI 0.56-1.21) or Gleason 8-10 prostate cancers (MHRR: 0.99, 95% CI 0.39-2.53) in men taking dutasteride over control groups. There were several limitations that need to be considered when interpreting these results.

CONCLUSION

These data provide support for the continued use of dutasteride in the treatment of symptomatic BPH patients.

Do adenocarcinomas of the prostate with Gleason score (GS) ≤6 have the potential to metastasize to lymph nodes?

Although rare, there are cases within reported series of men with Gleason score (GS) ≤6 on radical prostatectomies that show pelvic lymph node (LN) metastases. However, there are no studies on whether pelvic LN metastases occur in tumors with GS ≤6 using the International Society of Urological Pathology (ISUP) updated GS system. We performed a search of the radical prostatectomy databases at 4 large academic centers for cases of GS ≤6. Only prostatectomies submitted and embedded in entirety with pelvic LN dissections were included. A combined total of 14,123 cases were identified, of which 22 cases had a positive LN. Histopathologic review of 19 cases (3 cases unavailable for review) showed higher grade than originally reported by the pathologists in all cases. Of the 17 pre-ISUP reviewed cases, 2 were upgraded to 4+3=7 with both cribriform and poorly formed glands. One case was upgraded to 4+3=7 with tertiary pattern 5 displaying cribriform glands, poorly formed glands, and cords of single cells. Eleven cases were upgraded to 3+4=7 with glomeruloid structures and small to large cribriform glands (1 of these also had features of ductal adenocarcinoma). Two cases had tertiary pattern 4 with small cribriform glands. One case had a prominent colloid component that would currently be graded as 4+5=9 because of large cribriform glands and solid sheets of cells within the mucin. Of the 2 post-ISUP cases, 1 demonstrated tertiary pattern 4, and the other showed GS 3+4=7 with irregular cribriform glands. Undergrading is the primary reason for LN positivity with GS ≤6, which has decreased significantly since the adoption of the ISUP grading system in 2005. Of over 14,000 totally embedded radical prostatectomies from multiple institutions, there was not a single case of a GS ≤6 tumor with LN metastases. In contrast to prevailing assumptions, GS ≤6 tumors do not appear to metastasize to LNs. Rather, Gleason pattern 4 or 5, as better defined by the current ISUP updated grading system, is required for metastatic disease.

Gleason grading: past, present and future

In 1966 Donald Gleason developed his grading and scoring system for prostatic adenocarcinoma. This classification was refined in 1974 and gained almost universal acceptance, being classified as a category 1 prognostic parameter by the College of American Pathologists. Modifications to the classification were recommended at a conference convened by the International Society of Urological Pathology (ISUP) in 2005. This modified classification has resulted in a significant upgrading of tumours, although some studies have shown a greater concordance between needle biopsy and radical prostatectomy scores when compared to classical Gleason (CG) grading. The ISUP consensus conference recommended that for needle biopsies higher tertiary patterns should be incorporated into the final Gleason score, and this has been correlated with biochemical failure, tumour volume and mortality. Recently the validity of including cribriform glands as a component of Gleason pattern 3 has been questioned and it has been recommended that all tumours showing cribriform architecture should be classified as Gleason pattern 4. The recommendations arising from the 2005 Consensus Conference were largely unsupported by validating data, yet this new grading system has achieved widespread usage. It is unfortunate that recent suggestions for further modification are similarly lacking in supporting evidence. In view of this it is recommended that the Modified Gleason Scoring Classification should continue to be utilized in its original (2005) format and that any future alterations should be implemented only when mandated by tumour-related outcome studies.

Implications of the International Society of Urological Pathology modified Gleason grading system

CONTEXT

Histologic grading is the clinically most useful tissue-based predictor of prognosis for prostate cancer. Over the years, there has been a gradual shift in how the Gleason grading is applied in practice, with a general trend toward upgrading. A consensus conference was organized in 2005 by the International Society of Urological Pathology (ISUP) for standardizing both the perception of histologic patterns and how the grade information is compiled and reported.

OBJECTIVE

To review the implications of the ISUP modified Gleason grading system.

DATA SOURCES

Personal experience and review of the current literature.

CONCLUSIONS

The recommendations regarding pattern interpretation and reporting are summarized. The practical consequences of the ISUP modification of the Gleason grading are reported. The prognostic importance of the Gleason score, its reproducibility, and its preoperative assessment are discussed. Subsequent proposals for slight modifications to the ISUP grading system are described.

Interactive digital slides with heat maps: a novel method to improve the reproducibility of Gleason grading

Our aims were to analyze reporting of Gleason pattern (GP) 3 and 4 prostate cancer with the ISUP 2005 Gleason grading and to collect consensus cases for standardization. We scanned 25 prostate biopsy cores diagnosed as Gleason score (GS) 6-7. Fifteen genitourinary pathologists graded the digital slides and circled GP 4 and 5 in a slide viewer. Grading difficulty was scored as 1-3. GP 4 components were classified as type 1 (cribriform), 2 (fused), or 3 (poorly formed glands). A GS of 5-6, 7 (3 + 4), 7 (4 + 3), and 8-9 was given in 29%, 41%, 19%, and 10% (mean GS 6.84, range 6.44-7.36). In 15 cases, at least 67% of observers agreed on GS groups (consensus cases). Mean interobserver weighted kappa for GS groups was 0.43. Mean difficulty scores in consensus and non-consensus cases were 1.44 and 1.66 (p = 0.003). Pattern 4 types 1, 2, and 3 were seen in 28%, 86%, and 67% of GP 4. All three coexisted in 16% (11% and 23% in consensus and non-consensus cases, p = 0.03). Average estimated and calculated %GP 4/5 were 29% and 16%. After individual review, the experts met to analyze diagnostic difficulties. Areas of GP 4 and 5 were displayed as heat maps, which were helpful for identifying contentious areas. A key problem was to agree on minimal criteria for small foci of GP 4. In summary, the detection threshold for GP 4 in NBX needs to be better defined. This set of consensus cases may be useful for standardization.

The potential impact of reproducibility of Gleason grading in men with early stage prostate cancer managed by active surveillance: a multi-institutional study

PURPOSE

We evaluated the reproducibility of Gleason grading as relevant to the clinical treatment of men on active surveillance.

MATERIALS AND METHODS

Three sets of digital images of prostatic adenocarcinoma in biopsies were reviewed and assigned Gleason scores by a total of 11 pathologists from 7 institutions. Interobserver and intra-observer reproducibility were assessed for assignment of the highest Gleason pattern (3 vs 4 or higher). We also identified 97 consecutive patients on active surveillance. Prostate biopsy glass slides from 82 of the patients were available for re-review and the frequency of carcinoma requiring the distinction of tangentially sectioned Gleason pattern 3 from 4 was determined.

RESULTS

Interobserver reproducibility for classic Gleason patterns was substantial (Light's κ 0.76). Interobserver reproducibility for the histological distinction of tangentially sectioned Gleason pattern 3 from Gleason pattern 4 was only fair (Light's κ 0.27). Intra-observer reproducibility ranged from 65% to 100% (mean 81.5%). Of the 82 patients on active surveillance 61 had carcinoma and 15 (24.5%) had a set of biopsies with at least 1 focus in which the distinction between tangentially sectioned Gleason pattern 3 and poorly formed pattern 4 glands had to be considered.

CONCLUSIONS

The reproducibility of grading classic Gleason patterns is high. However, variability in grading occurred when distinguishing between tangentially sectioned pattern 3 glands and the poorly formed gland subset of pattern 4. Developing universally accepted histological and/or molecular criteria to distinguish these patterns and subsequently characterizing their natural history would be useful when treating patients on active surveillance.