Size-adjusted Quantitative Gleason Score as a Predictor of Biochemical Recurrence after Radical Prostatectomy

Amount of Gleason Pattern 3 Is Not Predictive of Risk in Grade Group 2-4 Prostate Cancer

We investigated whether total Gleason pattern 3 or the proportion of Gleason pattern 4 on biopsy is a significant predictor of adverse pathology. Our findings suggest that quantifying the amount rather than the proportion of Gleason pattern 4 would improve grade group assignment for decision-making in localized prostate cancer.

Contemporary Diagnostic Reporting for Prostatic Adenocarcinoma: Morphologic Aspects, Molecular Correlates, and Management Perspectives

The diagnosis and reporting of prostatic adenocarcinoma have evolved from the classic framework promulgated by Dr Donald Gleason in the 1960s into a complex and nuanced system of grading and reporting that nonetheless retains the essence of his remarkable observations. The criteria for the "Gleason patterns" originally proposed have been continually refined by consensuses in the field, and Gleason scores have been stratified into a patient-friendly set of prognostically validated and widely adopted Grade Groups. One product of this successful grading approach has been the opportunity for pathologists to report diagnoses that signal carefully personalized management, placing the surgical pathologist's interpretation at the center of patient care. At one end of the continuum of disease aggressiveness, personalized diagnostic care means to sub-stratify patients with more indolent disease for active surveillance, while at the other end of the continuum, reporting histologic markers signaling aggression allows sub-stratification of clinically significant disease. Whether contemporary reporting parameters represent deeper nuances of more established ones (eg, new criteria and/or quantitation of Gleason patterns 4 and 5) or represent additional features reported alongside grade (intraductal carcinoma, cribriform patterns of carcinoma), assessment and grading have become more complex and demanding. Herein, we explore these newer reporting parameters, highlighting the state of knowledge regarding morphologic, molecular, and management aspects. Emphasis is made on the increasing value and stakes of histopathologists' interpretations and reporting into current clinical risk stratification and treatment guidelines.

Predicting prostate cancer specific-mortality with artificial intelligence-based Gleason grading

Background

Gleason grading of prostate cancer is an important prognostic factor, but suffers from poor reproducibility, particularly among non-subspecialist pathologists. Although artificial intelligence (A.I.) tools have demonstrated Gleason grading on-par with expert pathologists, it remains an open question whether and to what extent A.I. grading translates to better prognostication.

Methods

In this study, we developed a system to predict prostate cancer-specific mortality via A.I.-based Gleason grading and subsequently evaluated its ability to risk-stratify patients on an independent retrospective cohort of 2807 prostatectomy cases from a single European center with 5–25 years of follow-up (median: 13, interquartile range 9–17).

Results

Here, we show that the A.I.’s risk scores produced a C-index of 0.84 (95% CI 0.80–0.87) for prostate cancer-specific mortality. Upon discretizing these risk scores into risk groups analogous to pathologist Grade Groups (GG), the A.I. has a C-index of 0.82 (95% CI 0.78–0.85). On the subset of cases with a GG provided in the original pathology report (n = 1517), the A.I.’s C-indices are 0.87 and 0.85 for continuous and discrete grading, respectively, compared to 0.79 (95% CI 0.71–0.86) for GG obtained from the reports. These represent improvements of 0.08 (95% CI 0.01–0.15) and 0.07 (95% CI 0.00–0.14), respectively.

Conclusions

Our results suggest that A.I.-based Gleason grading can lead to effective risk stratification, and warrants further evaluation for improving disease management.

Gleason grading is the process by which pathologists assess the morphology of prostate tumors. The assigned Grade Group tells us about the likely clinical course of people with prostate cancer and helps doctors to make decisions on treatment. The process is complex and subjective, with frequent disagreement amongst pathologists. In this study, we develop and evaluate an approach to Gleason grading based on artificial intelligence, rather than pathologists’ assessment, to predict risk of dying of prostate cancer. Looking back at tumors and data from 2,807 people diagnosed with prostate cancer, we find that our approach is better at predicting outcomes compared to grading by pathologists alone. These findings suggest that artificial intelligence might help doctors to accurately determine the probable clinical course of people with prostate cancer, which, in turn, will guide treatment.

Wulczyn et al. utilise a deep learning-based Gleason grading model to predict prostate cancer-specific mortality in a retrospective cohort of radical prostatectomy patients. Their model enables improved risk stratification compared to pathologists’ grading and demonstrates the potential for computational pathology in the management of prostate cancer.

Optimal Method for Reporting Prostate Cancer Grade in MRI-targeted Biopsies

When multiple cores are biopsied from a single magnetic resonance imaging (MRI)-targeted lesion, Gleason grade may be assigned for each core separately or for all cores of the lesion in aggregate. Because of the potential for disparate grades, an optimal method for pathology reporting MRI lesion grade awaits validation. We examined our institutional experience on the concordance of biopsy grade with subsequent radical prostatectomy (RP) grade of targeted lesions when grade is determined on individual versus aggregate core basis. For 317 patients (with 367 lesions) who underwent MRI-targeted biopsy followed by RP, targeted lesion grade was assigned as (1) global Grade Group (GG), aggregated positive cores; (2) highest GG (highest grade in single biopsy core); and (3) largest volume GG (grade in the core with longest cancer linear length). The 3 biopsy grades were compared (equivalence, upgrade, or downgrade) with the final grade of the lesion in the RP, using κ and weighted κ coefficients. The biopsy global, highest, and largest GGs were the same as the final RP GG in 73%, 68%, 62% cases, respectively (weighted κ: 0.77, 0.79, and 0.71). For cases where the targeted lesion biopsy grade scores differed from each other when assigned by global, highest, and largest GG, the concordance with the targeted lesion RP GG was 69%, 52%, 31% for biopsy global, highest, and largest GGs tumors (weighted κ: 0.65, 0.68, 0.59). Overall, global, highest, and largest GG of the targeted biopsy show substantial agreement with RP-targeted lesion GG, however targeted global GG yields slightly better agreement than either targeted highest or largest GG. This becomes more apparent in nearly one third of cases when each of the 3 targeted lesion level biopsy scores differ. These results support the use of global (aggregate) GG for reporting of MRI lesion-targeted biopsies, while further validations are awaited.

The 2019 Genitourinary Pathology Society (GUPS) White Paper on Contemporary Grading of Prostate Cancer

CONTEXT.—

Controversies and uncertainty persist in prostate cancer grading.

OBJECTIVE.—

To update grading recommendations.

DATA SOURCES.—

Critical review of the literature along with pathology and clinician surveys.

CONCLUSIONS.—

Percent Gleason pattern 4 (%GP4) is as follows: (1) report %GP4 in needle biopsy with Grade Groups (GrGp) 2 and 3, and in needle biopsy on other parts (jars) of lower grade in cases with at least 1 part showing Gleason score (GS) 4 + 4 = 8; and (2) report %GP4: less than 5% or less than 10% and 10% increments thereafter. Tertiary grade patterns are as follows: (1) replace "tertiary grade pattern" in radical prostatectomy (RP) with "minor tertiary pattern 5 (TP5)," and only use in RP with GrGp 2 or 3 with less than 5% Gleason pattern 5; and (2) minor TP5 is noted along with the GS, with the GrGp based on the GS. Global score and magnetic resonance imaging (MRI)-targeted biopsies are as follows: (1) when multiple undesignated cores are taken from a single MRI-targeted lesion, an overall grade for that lesion is given as if all the involved cores were one long core; and (2) if providing a global score, when different scores are found in the standard and the MRI-targeted biopsy, give a single global score (factoring both the systematic standard and the MRI-targeted positive cores). Grade Groups are as follows: (1) Grade Groups (GrGp) is the terminology adopted by major world organizations; and (2) retain GS 3 + 5 = 8 in GrGp 4. Cribriform carcinoma is as follows: (1) report the presence or absence of cribriform glands in biopsy and RP with Gleason pattern 4 carcinoma. Intraductal carcinoma (IDC-P) is as follows: (1) report IDC-P in biopsy and RP; (2) use criteria based on dense cribriform glands (>50% of the gland is composed of epithelium relative to luminal spaces) and/or solid nests and/or marked pleomorphism/necrosis; (3) it is not necessary to perform basal cell immunostains on biopsy and RP to identify IDC-P if the results would not change the overall (highest) GS/GrGp part per case; (4) do not include IDC-P in determining the final GS/GrGp on biopsy and/or RP; and (5) "atypical intraductal proliferation (AIP)" is preferred for an intraductal proliferation of prostatic secretory cells which shows a greater degree of architectural complexity and/or cytological atypia than typical high-grade prostatic intraepithelial neoplasia, yet falling short of the strict diagnostic threshold for IDC-P. Molecular testing is as follows: (1) Ki67 is not ready for routine clinical use; (2) additional studies of active surveillance cohorts are needed to establish the utility of PTEN in this setting; and (3) dedicated studies of RNA-based assays in active surveillance populations are needed to substantiate the utility of these expensive tests in this setting. Artificial intelligence and novel grading schema are as follows: (1) incorporating reactive stromal grade, percent GP4, minor tertiary GP5, and cribriform/intraductal carcinoma are not ready for adoption in current practice.

Practice patterns related to prostate cancer grading: results of a 2019 Genitourinary Pathology Society clinician survey

PURPOSE

To survey urologic clinicians regarding interpretation of and practice patterns in relation to emerging aspects of prostate cancer grading, including quantification of high-grade disease, cribriform/intraductal carcinoma, and impact of magnetic resonance imaging-targeted needle biopsy.

MATERIALS AND METHODS

The Genitourinary Pathology Society distributed a survey to urology and urologic oncology-focused societies and hospital departments. Eight hundred and thirty four responses were collected and analyzed using descriptive statistics.

RESULTS

Eighty percent of survey participants use quantity of Gleason pattern 4 on needle biopsy for clinical decisions, less frequently with higher Grade Groups. Fifty percent interpret "tertiary" grade as a minor/<5% component. Seventy percent of respondents would prefer per core grading as well as a global/overall score per set of biopsies, but 70% would consider highest Gleason score in any single core as the grade for management. Seventy five percent utilize Grade Group terminology in patient discussions. For 45%, cribriform pattern would affect management, while for 70% the presence of intraductal carcinoma would preclude active surveillance.

CONCLUSION

This survey of practice patterns in relationship to prostate cancer grading highlights similarities and differences between contemporary pathology reporting and its clinical application. As utilization of Gleason pattern 4 quantification, minor tertiary pattern, cribriform/intraductal carcinoma, and the incorporation of magnetic resonance imaging-based strategies evolve, these findings may serve as a basis for more nuanced communication and guide research efforts involving pathologists and clinicians.

Up-regulation of LIMK1 expression in prostate cancer is correlated with poor pathological features, lymph node metastases and biochemical recurrence

This study aimed to explore the association between LIM domain kinase 1 (LIMK1) expression in prostate cancer (PCa) tissues with advanced pathological features, lymph node metastases and biochemical recurrence. A total of 279 PCa specimens from patients who underwent radical prostatectomy and 50 benign prostatic hyperplasia (BPH) specimens were collected to construct tissue microarray, which were subjected to immunohistochemical staining for LIMK1 expression subsequently. Logistic and Cox regression analysis were used to evaluate the relationship between LIMK1 expression and clinicopathological features of patients with PCa. Immunohistochemical staining assay demonstrated that LIMK1 expression was significantly higher in PCa than BPH specimens (77.1% vs 26.0%; P < .001). LIMK1 expression was significantly higher in positive lymph node specimens than corresponding PCa specimens (P = .002; P < .001). Up‐regulation of LIMK1 was associated with prostate volume, prostate‐specific antigen, prostate‐specific antigen density, Gleason score, T stage, lymph node metastases, extracapsular extension and seminal vesicle invasion, and positive surgical margin. Multivariate logistic regression analysis demonstrated that LIMK1 was an independent risk factor for PCa lymph node metastasis (P < .05). Multivariate Cox regression analysis revealed that the up‐regulation of LIMK1 was an independent risk factor for biochemical recurrence. Kaplan‐Meier analysis indicated that up‐regulation LIMK1 was associated with shortened biochemical‐free survival (BFS) after radical prostatectomy (P < .001). In conclusion, LIMK1 was significantly up‐regulated in PCa and positive lymph node specimens and correlated with lymph node metastasis and shortened BFS of PCa. The underlying molecular mechanism of LIMK1 in PCa should be further evaluated.

[Grading of prostate cancer. For a more precise prognosis]

The simplification of the Gleason grading system, together with the reclassification of some of its patterns, has improved correlation with the clinical reality of prostate cancer, whilst maintaining the basic principles established fifty years ago. The subsequent grouping of the patterns into five degrees has allowed a more rational unification and enhanced the physician/patient communication. However, a greater precision in the assessment of the prognosis for each patient is still necessary and, to this end, elements that allow greater discrimination are continually being sought. The purpose of this brief review is to discuss the value and possible future incorporation in international recommendations of the percentage of pattern 4, the quantification of the cribriform pattern, the detection of intraductal carcinoma, the regrouping of some 'scores' and the possible stratification of the grade group 1.

Prostate Cancers Detected by Magnetic Resonance Imaging–Targeted Biopsies Have a Higher Percentage of Gleason Pattern 4 Component and Are Less Likely to Be Upgraded in Radical Prostatectomies

Context.—

In Gleason score (GS) 7 prostate cancers, the quantity of Gleason pattern 4 (GP 4) is an important prognostic factor and influences treatment decisions. Magnetic resonance imaging (MRI)–targeted biopsy has been increasingly used in clinical practice.

Objective.—

To investigate whether MRI-targeted biopsy may detect GS 7 prostate cancer with greater GP 4 quantity, and whether it improves biopsy/radical prostatectomy GS concordance.

Design.—

A total of 243 patients with paired standard and MRI-targeted biopsies with cancer in either standard or targeted or both were studied, 65 of whom had subsequent radical prostatectomy. The biopsy findings, including GS and tumor volume, were correlated with the radical prostatectomy findings.

Results.—

More prostate cancers detected by MRI-targeted biopsy were GS 7 or higher. Mean GP 4 percentage in GS 7 cancers was 31.0% ± 29.3% by MRI-targeted biopsy versus 25.1% ± 29.5% by standard biopsy. A total of 122 of 218 (56.0%) and 96 of 217 (44.2%) prostate cancers diagnosed on targeted biopsy and standard biopsy, respectively, had a GP 4 of 10% or greater (P = .01). Gleason upgrading was seen in 12 of 59 cases (20.3%) from MRI-targeted biopsy and in 24 of 57 cases (42.1%) from standard biopsy (P = .01). Gleason upgrading correlated with the biopsy cancer volume inversely and GP 4 of 30% or less in standard biopsy. Such correlation was not found in MRI-targeted biopsy.

Conclusions.—

Magnetic resonance imaging–targeted biopsy may detect more aggressive prostate cancers and reduce the risk of Gleason upgrading in radical prostatectomy. This study supports a potential role for MRI-targeted biopsy in the workup of prostate cancer and inclusion of percentage of GP 4 in prostate biopsy reports.

Reduced Connexin 43 expression is associated with tumor malignant behaviors and biochemical recurrence-free survival of prostate cancer

Connexin 43, a gap junction protein, coordinates cell-to-cell communication and adhesion. Altered Connexin 43 expression associated with cancer development and progression. In this study, we assessed Connexin 43 expression for association with clinicopathological features and biochemical recurrence of prostate cancer after radical prostatectomy. Pathological specimens were collected from 243 patients who underwent radical prostatectomy and from 60 benign prostatic hyperplasia (BPH) patients to construct tissue microarrays and immunohistochemical analysis of Connexin 43 expression. Kaplan-Meier curves and multivariable Cox proportion hazard model were performed to associate Connexin 43 expression with postoperative biochemical recurrence-free survival (BFS). Connexin 43 expression was significantly reduced or lost in tumor tissues compared to that of BPHs (39.1% vs. 96.7%, P<0.001). Reduced Connexin 43 expression was associated with high levels of preoperative PSA, high Gleason score, advanced pT stage, positive surgical margin, extracapsular extension, and seminal vesicle invasion (P < 0.05, for all). Kaplan-Meier curves showed that reduced Connexin 43 expression was associated with shortened postoperative BFS (P < 0.001). Multivariate analysis showed that reduced Connexin 43 expression, high Gleason score and advanced pT stage were independent predictors for BFS of patients (P < 0.05). Connexin 43 expression was significantly reduced or lost in prostate cancer tissues, which was associated with advanced clinicopathological features and poor BFS of patients after radical prostatectomy.

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.

The Gleason pattern 4 in radical prostatectomy specimens in current practice - Quantification, morphology and concordance with biopsy

PURPOSE

The upgrading of a prostate acinar adenocarcinoma grade group 1 (GG1) between needle biopsy and prostatectomy is common. The extent of high-grade tumor and cribriform morphology are currently suggested as prognostic factors.

METHODS

We reviewed 159 prostatectomy specimens from a private laboratory and an academic/public institution in Salvador, Bahia.

RESULTS

Tumors signed as GG1 at biopsy were upgraded in 59% of all cases. These tumors showed a low frequency of non-focal extraprostatic extension (one case, 3%), extensive positive surgical margins (two cases, 6%) and seminal vesicle invasion (one case, 3%). Among GG2 and GG3 tumors at prostatectomy, the percentage of Gleason pattern 4 (Gp4) involving the gland at ≤1%, 2-5% and >5% was associated with extensive extraprostatic extension (9%, 8% and 42%, respectively) and seminal vesicle invasion (1%, 10% and 31%, respectively). The volume of Gp4 of ≤1ml, >1 to 2ml and >2ml was associated with extensive extraprostatic extension (8%, 26% and 38%, respectively), seminal vesicle invasion (2%, 21% and 33%, respectively) and non-focal positive surgical margins (12%, 26% and 29%, respectively). Some GG2 tumors (~20%) indeed showed at least one measurement of Gp4 higher than one quarter of GG3 carcinomas. Cribriform morphology showed no significant associations for other adverse pathologic prognostic factors.

CONCLUSION

Upgrading from GG1 to GG2 is associated with a very low frequency of morphologic features associated with poor prognosis. Routine quantification of Gp4 is feasible in radical prostatectomy products and seems to better stratify tumors regarding the association with other morphologic parameters of prognostic importance.

Whom to Treat: Postdiagnostic Risk Assessment with Gleason Score, Risk Models, and Genomic Classifier

Management of prostate cancer presents unique challenges because of the disease's variable natural history. Accurate risk stratification at the time of diagnosis in clinically localized disease is crucial in providing optimal counseling about management options. To accurately distinguish pathologically indolent tumors from aggressive disease, risk groups are no longer sufficient. Rather, multivariable prognostic models reflecting the complete information known at time of diagnosis offer improved accuracy and interpretability. After diagnosis, further testing with genomic assays or other biomarkers improves risk classification. These postdiagnostic risk assessment tools should not supplant shared decision making, but rather facilitate risk classification and enable more individualized care.

Contemporary Gleason Grading of Prostatic Carcinoma: An Update With Discussion on Practical Issues to Implement the 2014 International Society of Urological Pathology (ISUP) Consensus Conference on Gleason Grading of Prostatic Carcinoma

The primary proceedings of the 2014 International Society of Urological Pathology Grading Conference were published promptly in 2015 and dealt with: (1) definition of various grading patterns of usual acinar carcinoma, (2) grading of intraductal carcinoma; and (3) support for the previously proposed new Grade Groups. The current manuscript in addition to highlighting practical issues to implement the 2014 recommendations, provides an updated perspective based on numerous studies published after the 2014 meeting. A major new recommendation that came from the 2014 Consensus Conference was to report percent pattern 4 with Gleason score 7 in both needle biopsies and radical prostatectomy (RP) specimens. This manuscript gives the options how to record percentage pattern 4 and under which situations recording this information may not be necessary. Another consensus from the 2014 meeting was to replace the term tertiary-grade pattern with minor high-grade pattern. Minor high-grade indicates that the term tertiary should not merely be just the third most common pattern but that it should be minor or limited in extent. Although a specific cutoff of 5% was not voted on in the 2014 Consensus meeting, the only quantification of minor high-grade pattern that has been used in the literature with evidence-based data correlating with outcome has been the 5% cutoff. At the 2014 Consensus Conference, there was agreement that the grading rule proposed in the 2005 Consensus Conference on needle biopsies be followed, that tertiary be not used, and that the most common and highest grade patterns be summed together as the Gleason score. Therefore, the term tertiary or minor high-grade pattern should only be used in RP specimens when there are 3 grade patterns, such as with 3+4=7 or 4+3=7 with <5% Gleason pattern 5. It was recommended at the 2014 Conference that for the foreseeable future, the new Grade Groups would be reported along with the Gleason system. The minor high-grade patterns do not change the Grade Groups, such that in current practice one would, for example, report Gleason score 3+4=7 (Grade Group 2) with minor (tertiary) pattern 5. It was discussed at the 2014 Consensus Conference how minor high-grade patterns would be handled if Grade Groups 1 to 5 eventually were to replace Gleason scores 2 to 10. In the above example, it could be reported as Grade Group 2 with minor high-grade pattern or potentially this could be abbreviated to Grade Group 2+. The recommendation from the 2014 meeting was the same as in the 2005 consensus for grading separate cores with different grades: assign individual Gleason scores to separate cores as long as the cores were submitted in separate containers or the cores were in the same container yet specified by the urologist as to their location (ie, by different color inks). It is the practice of the majority of the authors of this manuscript that if the cores are submitted in a more specific anatomic manner than just left versus right (ie, per sextant site, MRI targets, etc.), that the grade of multiple cores in the same jar from that specific site are averaged together, given they are from the same location within the prostate. In cases with multiple fragmented cores in a jar, there was agreement to give a global Gleason score for that jar. The recommendation from the 2014 meeting was the same as in the 2005 consensus for grading separate nodules of cancer in RP specimens: one should assign a separate Gleason score to each dominant nodule(s). In the unusual occurrence of a nondominant nodule (ie, smaller nodule) that is of higher stage, one should also assign a grade to that nodule. If one of the smaller nodules is the highest grade focus within the prostate, the grade of this smaller nodule should also be recorded. An emerging issue in the studies and those published subsequent to the meeting was that cribriform morphology is associated with a worse prognosis than poorly formed or fused glands and in the future may be specifically incorporated into grading practice. We believe that the results from the 2014 Consensus Conference and the updates provided in this paper are vitally important to our specialty to promote uniformity in reporting of prostate cancer grade and in the contemporary management of prostate cancer.