Validation of the 2015 prostate cancer grade groups for predicting long-term oncologic outcomes in a shared equal-access health system

Metabolic syndrome is associated with aggressive prostate cancer regardless of race

PURPOSE

Recent meta-analyses suggest the Metabolic Syndrome (MS) increases high-grade prostate cancer (PC), although studies are inconsistent and few black men were included. We investigated MS and PC diagnosis in black and white men undergoing prostate biopsy in an equal access healthcare system. We hypothesized MS would be linked with aggressive PC, regardless of race.

METHODS

Among men undergoing prostate biopsy at the Durham Veterans Affairs Hospital, medical record data abstraction of diagnosis or treatment for hypertension (≥ 130/85 mmHg), dyslipidemia (HDL < 40 mg/dL), hypertriglyceridemia (≥ 150 mg/dL), diabetes, hyperglycemia (fasting glucose ≥ 100 ml/dL), and central obesity (waist circumference ≥ 40 inches) were done. Biopsy grade group (GG) was categorized as low (GG1) or high (GG2-5). Multinomial logistic regression was used to examine MS (3-5 components) vs. no MS (0-2 components) and diagnosis of high grade and low grade vs. no PC, adjusting for potential confounders. Interactions between race and MS were also tested.

RESULTS

Of 1,051 men (57% black), 532 (51%) had MS. Men with MS were older, more likely to be non-black, and had a larger prostate volume (all p ≤ 0.011). On multivariable analysis, MS was associated with high-grade PC (OR = 1.73, 95% CI 1.21-2.48, p = 0.003), but not overall PC (OR = 1.17, 95% CI 0.88-1.57, p = 0.29) or low grade (OR = 0.87, 95% CI 0.62-1.21, p = 0.39). Results were similar in black and non-black men (all p-interactions > 0.25).

CONCLUSION

Our data suggest that metabolic dysregulation advances an aggressive PC diagnosis in both black and non-black men. If confirmed, prevention of MS could reduce the risk of developing aggressive PC, including black men at higher risk of PC mortality.

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.

Benefits and harms of the new prostate cancer grade grouping on the prediction of long-term oncological outcomes in patients after radical prostatectomy

OBJECTIVE

To investigate whether the new prostate cancer grade groups model provides significant predictive value and better patient stratification on tumor progression after radical prostatectomy compared with the former Gleason grading models.

METHODS

Men treated at a tertiary center by radical prostatectomy between 2005 and 2017 were analyzed. The outcomes of interest were clinical progression-free and cancer-specific survival. Multivariate Cox regression analysis, C-index and decision curve analysis were carried out using three-tier (Gleason score 6, 7 and 8-10), four-tier (Gleason score 6, 7, 8 and 9-10) and new grade groups model.

RESULTS

In total, 1759 men were included in the analysis. At a median of 87 months (interquartile range 51-134 months) of follow up, clinical progression was detected in 78 (4.4%) and cancer-related death in 42 (2.4%) patients. The hazard ratio of clinical progression-free was 2.3, 5.7, 5.2 and 29.5; the hazard ratio of cancer-specific survival was 1.7, 3.2, 4.8 and 11.8 in the grade groups 2-5, relative to grade group 1, respectively. The grade groups model had higher C-index in comparison with four- and three-tier grading models for clinical progression-free survival 0.88 versus 0.85 versus 0.83 and for cancer-specific survival 0.82 versus 0.80 versus 0.80, respectively. In the decision curve analysis, the grade groups model shows marginally better net benefit on clinical progression-free and cancer-specific survival.

CONCLUSIONS

The new model shows better performance in comparison with former Gleason grading models on the prediction of long-term oncological outcomes.

Biopsy Grade Group as a reliable prognostic factor for BCR in Afro-Caribbean men with intermediate- and high-risk prostate cancer

PURPOSE

The Grade Group (GG) classification is recommended by guidelines as a reliable prognostic factor of prostate cancer. However, most studies have been performed on the Caucasian population. Our objective was to validate GG classification as a safe way to classify intermediate- and high-risk patients with African ancestry.

PATIENTS AND METHODS

This was a retrospective study in an Afro-Caribbean population. A total of 1236 patients were included between 2000 and 2015. Patients were stratified according to (GG). Survival analysis was performed using the Kaplan-Meier method, univariate and multivariate analyses using the Cox model.

RESULTS

There was no significant difference at 5 and 10-year BCR-free survival between the intermediate- and high-risk groups, based on the D'Amico classification. There was a highly significant difference in BCR-free survival at 5 (p < 0.0001) and 10 years (p < 0.0001) for patients of GG 1 and 2 vs 3, 4, and 5, respectively. There was no significant difference in 5-year BCR-free survival of patients of GG grades 1 and 2, whether lymph-node dissection was performed or not. There was a significant difference between GG 2 and 3 patients in 5 (p = 0.008) and 10-year BCR-free survival (p = 0.01). High PSA (p < 0.0001), pathological GG ≥ 3 (p < 0.0001), pathological stage pT3 (p < 0.0001) and positive margins (p < 0.0001) were factors for BCR in multivariate analysis.

CONCLUSION

The GG 2015 classification appears to be a better prognostic factor than D'Amico classification for intermediate- and high-risk Afro-Caribbean patients.

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.

Use of multiparametric magnetic resonance imaging and fusion-guided biopsies to properly select and follow African-American men on active surveillance

OBJECTIVES

To determine the rate of Gleason Grade Group (GGG) upgrading in African-American (AA) men with a prior diagnosis of low-grade prostate cancer (GGG 1 or GGG 2) on 12-core systematic biopsy (SB) after multiparametric magnetic resonance imaging (mpMRI) and fusion biopsy (FB); and whether AA men who continued active surveillance (AS) after mpMRI and FB fared differently than a predominantly Caucasian (non-AA) population.

PATIENTS AND METHODS

A database of men who had undergone mpMRI and FB was queried to determine rates of upgrading by FB amongst men deemed to be AS candidates based on SB prior to referral. After FB, Kaplan-Meier curves were generated for AA men and non-AA men who then elected AS. The time to GGG upgrading and time continuing AS were compared using the log-rank test.

RESULTS

AA men referred with GGG 1 disease on previous SB were upgraded to GGG ≥3 by FB more often than non-AA men, 22.2% vs 12.7% (P = 0.01). A total of 32 AA men and 258 non-AA men then continued AS, with a median (interquartile range) follow-up of 39.19 (24.24-56.41) months. The median time to progression was 59.7 and 60.5 months, respectively (P = 0.26). The median time continuing AS was 61.9 months and not reached, respectively (P = 0.80).

CONCLUSIONS

AA men were more likely to be upgraded from GGG 1 on SB to GGG ≥3 on initial FB; however, AA and non-AA men on AS subsequently progressed at similar rates following mpMRI and FB. A greater tendency for SB to underestimate tumour grade in AA men may explain prior studies that have shown AA men to be at higher risk of progression during AS.

The new ISUP 2014/WHO 2016 prostate cancer grade group system: first résumé 5 years after introduction and systemic review of the literature

PURPOSE

To systematically and comprehensively review and summarize the most recent literature assessing the value of the new grading system introduced by the International Society of Urological Pathology (ISUP) in 2014 and accepted by the World Health Organization (WHO) in 2016.

METHODS

A systematic literature search in the PubMed database was performed up to November 2018. Overall, 15 studies in the period from 2016 to 2018 evaluating the new grading system have been selected for evidence synthesis.

RESULTS

The main goals of the new ISUP 2014/WHO 2016 grading system were to establish (I) a more accurate and simplified grade stratification, (II) less overtreatment of indolent prostate cancer as well as (III) an improved patient communication. The majority of the studies chose biochemical recurrence as an endpoint for evaluation and statistically assigns the new ISUP 2014/WHO 2016 grading system a higher prognostic accuracy than the former Gleason grading. However, in only a subset of studies it was clearly evident that the historical samples were not only re-grouped according to the new grade groups but also re-graded according to the new histomorphological 2014 ISUP criteria.

CONCLUSIONS

The vast majority of the studies support an improved prognostic accuracy of the ISUP 2014/WHO 2016 grade groups and endorse its worldwide application.

Persistent Homology for the Quantitative Evaluation of Architectural Features in Prostate Cancer Histology

The current system for evaluating prostate cancer architecture is the Gleason grading system which divides the morphology of cancer into five distinct architectural patterns, labeled 1 to 5 in increasing levels of cancer aggressiveness, and generates a score by summing the labels of the two most dominant patterns. The Gleason score is currently the most powerful prognostic predictor of patient outcomes; however, it suffers from problems in reproducibility and consistency due to the high intra-observer and inter-observer variability amongst pathologists. In addition, the Gleason system lacks the granularity to address potentially prognostic architectural features beyond Gleason patterns. We evaluate prostate cancer for architectural subtypes using techniques from topological data analysis applied to prostate cancer glandular architecture. In this work we demonstrate the use of persistent homology to capture architectural features independently of Gleason patterns. Specifically, using persistent homology, we compute topological representations of purely graded prostate cancer histopathology images of Gleason patterns 3,4 and 5, and show that persistent homology is capable of clustering prostate cancer histology into architectural groups through a ranked persistence vector. Our results indicate the ability of persistent homology to cluster prostate cancer histopathology images into unique groups with dominant architectural patterns consistent with the continuum of Gleason patterns. In addition, of particular interest, is the sensitivity of persistent homology to identify specific sub-architectural groups within single Gleason patterns, suggesting that persistent homology could represent a robust quantification method for prostate cancer architecture with higher granularity than the existing semi-quantitative measures. The capability of these topological representations to segregate prostate cancer by architecture makes them an ideal candidate for use as inputs to future machine learning approaches with the intent of augmenting traditional approaches with topological features for improved diagnosis and prognosis.

Optimization of the 2014 Gleason grade grouping in a Canadian cohort of patients with localized prostate cancer

OBJECTIVES

To evaluate the five-tier Gleason grade group (GG) scoring of prostate cancers adopted by the International Society of Urology Pathology (ISUP) in 2014, and to propose modifications to optimize its performance.

PATIENTS AND METHODS

Data were obtained from PROCURE, a prospective cohort of patients with localized prostate cancer undergoing radical prostatectomy in Québec, 2006-2013. Surgical specimens were evaluated by genitourinary pathologists using 2014 ISUP criteria. Treatment failure was defined as biochemical recurrence and/or initiation of secondary, non-adjuvant therapy. Analyses were conducted using Kaplan-Meier methods, log-rank tests, Cox proportional hazards models and Harrell's concordance indices.

RESULTS

A total of 1 917 patients were included, with a median follow-up of 69 months. The 5-year treatment failure rates were 9.6%, 23.5%, 43.1%, 52.6% and 84.3% in GG1-5, respectively (P < 0.001 when comparing GG2 with GG3). Treatment failure rates for patients in GG2 and GG3 with tertiary Gleason 5 pattern were higher than patients in the same group without a tertiary pattern (P < 0.001), but were similar to rates for patients in GGs 3 or 4 without a tertiary pattern (P > 0.3). Primary Gleason pattern (4/5) predicted treatment failure in GG5 (5-year failure rates 82.3% vs 97.1%, respectively; P = 0.001). The five-tier GG system had greater accuracy as a prognostic indicator compared with the four-tier system (Harrell's concordance index 0.716 vs 0.676). When upgrading patients in GG2/3 with tertiary Gleason 5 pattern to patients in GG3/4, and separating patients in GG5 by primary Gleason pattern, the Harrell's concordance index increased to 0.730.

CONCLUSION

The five-tier GG system increased accuracy for predicting treatment failure compared with the previous grading systems, but can be further improved.

How Are Gleason Scores Categorized in the Current Literature: An Analysis and Comparison of Articles Published in 2016-2017

BACKGROUND

A new prostate cancer grading system was proposed in 2013 and endorsed by major journals and societies in 2014, in part because of anecdotal evidence that Gleason scores (GSs) were incorrectly combined in the literature.

OBJECTIVE

To examine how published studies categorized GSs in current practice.

DESIGN, SETTING, AND PARTICIPANTS

A PubMed search was conducted on articles published in 2016-2017 using the search terms "Gleason" and "prostate". This literature review included 1576 articles after exclusions.

RESULTS

(1) Separating GS 7: pathology journals were more likely than non-pathology journals to grade GS 7 separately (56.9% vs 40.0%, p<0.05). Articles co-authored by a pathologist separated GS 7 more than those without a pathologist (53.2% vs 32.9%, p<0.001). North American and European studies separated GS 7 more than Asian studies (47.6% and 44.1% vs 24.1%, p<0.001). Clinical articles separated GS 7 more than research articles (43.7% vs 32.9%, p<0.001). (2) Separating GS 8 from GS 9-10: pathology journals separated GS 8 from GS 9-10 more than non-pathology journals (55.2% vs 34.4%, p=0.001). Articles co-authored by a pathologist separated GS 8 from GS 9-10 more often than those without a pathologist (44.9% vs 29.5%, p<0.001). (3) Using grade groups as "ideal" with all other groupings "non-ideal": pathology journals used ideal more than non-pathology journals (32.2% vs 15.9%, p<0.001). Ideal grouping is more likely in articles co-authored by a pathologist than in those without a pathologist (20.6% vs 11.0%, p<0.001). North American and European studies used ideal grouping more than Asian studies (17.6% and 14.0% vs 9.1%, p<0.05). (4) Arranging groupings in decreasing order from ideal to non-ideal: pathology journals were closer to ideal than non-pathology journals (p=0.002). Articles co-authored by a pathologist were classified closer to ideal than those without a pathologist (p<0.001). North American (p<0.001) and European (p=0.02) studies were closer to ideal than Asian studies.

CONCLUSIONS

There is still wide variation in how GSs are grouped world-wide. Only a minority of published articles group GSs accurately.

PATIENT SUMMARY

In this report, we looked at how GSs were grouped world-wide. We found that only a minority of published articles on prostate cancer were grouping GSs accurately, which could lead to inaccurate results and affect patient care with different prostate cancer grades. Our study calls for more widespread adoption of the new prostate cancer grading system composed of five grade groups to minimize incorrect grouping for future studies.

Prostate cancer grading in 2018: limitations, implementations, cribriform morphology, and biological markers

The Gleason grading system is among the most important prognostic factors in patients with prostate cancer. From the 2005 to the 2014 consensus conferences, organized by the International Society of Urological Pathology, the morphologic criteria for the identification of the Gleason patterns were redefined, thus resulting in the shrinkage of the Gleason pattern 3. This led to the expansion of the Gleason pattern 4. The newly proposed grade group system reduces the Gleason scores of prostate cancer to the lowest number, each associated with a unique behavior from the prognostic point of view. The advantage is that the simplified system with five groups allows for a more accurate stratification of the patients in comparison with the Gleason system. Cribriform, fused, ill-defined and glomeruloid glands are part of the histologic spectrum of the Gleason pattern 4. Cribriform morphology has a prognosis that is worse in comparison with the other non-cribriform Gleason 4 patterns. One of the major implications of the cribriform growth is that it precludes a patient from choosing active surveillance.

Future Perspectives and Challenges of Prostate MR Imaging

MR imaging is an important part of prostate cancer diagnosis. Variations in quality and skill in general practice mean results are not as impressive as they were in academic centers. This observation provides an impetus to improve the method. Improved quality assurance will likely result in better outcomes. Improved characterization of clinically significant prostate cancer may assist in making MR imaging more useful. Improved methods of registering MR imaging with transrectal ultrasound imaging and robotic arms controlling the biopsy can reduce the impact of inexperienced operators and make the entire system of MR imaging-guided biopsies more robust.