Changes in prostate cancer grading: Including a new patient-centric grading system

Cardiovascular risk of gonadotropin-releasing hormone antagonist versus agonist in men with prostate cancer: an observational study in Taiwan

BACKGROUND

The impact of gonadotropin-releasing hormone (GnRH) antagonist and agonist (GnRHa) treatment on cardiovascular disease (CVD) risk in prostate cancer (PCa) remains inconclusive due to conflicting findings. We compared the effects of GnRH antagonist and GnRHa treatments on CVD risk in patients with PCa and pre-existing CVD, in a Taiwan population-based database.

METHODS

We assessed the risk of major adverse CV events (MACE: ischemic heart disease [IHD], stroke, congestive heart failure [CHF] or all cause deaths) and composite CV events (IHD, stroke, CHF or CV deaths) occurring ≥90 days after androgen deprivation therapy (ADT) initiation in patients with PCa after 90 days of treatment with either GnRH antagonist (degarelix; n = 499) or GnRHa (goserelin, leuprolide, triptorelin; n = 15,127). Patients identified with pre-existing CVD had received cardiac therapy for IHD, reported a stroke or CHF within a year before ADT initiation. Adjusted hazard ratios (aHR) and 95% confidence interval (CI) were obtained for MACE and composite CV events risk after adjusting for age, baseline status of diabetes, hypertension and treatments received.

RESULTS

All GnRH antagonist-treated patients showed lower risk of composite CV events than the GnRHa-treated patients. The lower composite CV events risk associated with GnRH antagonist was also observed in patients with metastasis at diagnosis (aHR 0.16; 95% CI, 0.04-0.38; p = 0.013) and those receiving ADT for more than six months (aHR 0.30; 95% CI, 0.16-0.54; p < 0.0001). In patients with pre-existing CVD, the MACE risk was 33% lower (aHR 0.67; 95% CI, 0.46-0.96; p = 0.0299) and composite CV events risk was 84% lower (aHR 0.16; 95% CI, 0.05-0.50; p = 0.0017) in GnRH antagonist-treated than the GnRHa-treated patients.

CONCLUSIONS

In patients with PCa and pre-existing CVD, GnRH antagonist use was associated with lower risks for composite CV events and MACE compared with GnRHa.

Predicting Insignificant Prostate Cancer: Analysis of the Pathological Outcomes of Candidates for Active Surveillance according to the Pre-International Society of Urological Pathology (Pre-ISUP) 2014 Era Versus the Post-ISUP2014 Era

Purpose

To analyze the difference in the prediction accuracy with an active surveillance (AS) protocol between two eras (pre-International Society of Urological Pathology [pre-ISUP]-2014 vs. post-ISUP2014).

Materials and Methods

We retrospectively analyzed 118 candidates for AS who underwent radical prostatectomy between 2009 and 2017. We divided our patients into two groups (group 1 [n=57], operation date 2009–2015; group 2 [n=61], operation date 2016–2017). Pathologic slides in group 1 were reviewed to distinguish men with cribriform pattern (CP) because the determination of Gleason scores in old era had been based on pre-ISUP2014 classification. Postoperative outcomes in the two eras were analyzed twice: first, all men in group 1 vs. group 2; second, the remaining men after excluding those with CPs in group 1 vs. group 2.

Results

The proportion of men with insignificant prostate cancer (iPCa) was significantly lower in group 1 than in group 2 (36.8% vs. 57.4%, p=0.040). After excluding 11 men with CPs from group 1, those remaining (46 men) were compared again with group 2. In this analysis, the proportion of men with iPCa was similar between the two groups (old vs. contemporary era: 41.3% vs. 57.4%, p=0.146). Nine of 11 men with CP had violated the criteria for iPCa in the earlier comparison.

Conclusions

The accuracy of the AS protocol has been affected by the coexistence of CPs and pure Gleason 6 tumors in the pre-ISUP2014 era. We suggest to use only contemporary (post-ISUP2014) data to analyze the accuracy with AS protocols in future studies.

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

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

3-D Multi-parametric Contrast-Enhanced Ultrasound for the Prediction of Prostate Cancer

Trans-rectal ultrasound-guided 12-core systematic biopsy (SBx) is the standard diagnostic pathway for prostate cancer (PCa) because of a lack of sufficiently accurate imaging. Quantification of 3-D dynamic contrast-enhanced ultrasound (US) might open the way for a targeted procedure in which biopsies are directed at lesions suspicious on imaging. This work describes the expansion of contrast US dispersion imaging algorithms to 3-D and compares its performance against malignant and benign disease. Furthermore, we examined the feasibility of a multi-parametric approach to predict SBx-core outcomes using machine learning. An area under the receiver operating characteristic (ROC) curve of 0.76 and 0.81 was obtained for all PCa and significant PCa, respectively, an improvement over previous US methods. We found that prostatitis, in particular, was a source of false-positive readings.

Historical and contemporary perspectives on cribriform morphology in prostate cancer

The Gleason scoring system is widely used for the grading and prognostication of prostate cancer. A Gleason pattern 4 subtype known as cribriform morphology has now been recognized as an aggressive and often lethal pattern of prostate cancer. The vast majority of published and ongoing prostate cancer studies still do not acknowledge the prognostic differences between various Gleason pattern 4 morphologies. As a result, current treatment recommendations are likely to be imprecise and not tailored towards patients who are most likely to die from the disease. Use of active surveillance for patients with Gleason score 3 + 4 prostate cancer has been suggested. However, the success of such paradigms would require cribriform morphology to be reported at the time of prostate biopsy, as patients harbouring such a pattern are poor candidates for surveillance. To date, only a limited number of studies have described the molecular alterations that occur in the cribriform morphological pattern. Further refinement of prostate cancer grading paradigms to distinguish cribriform from noncribriform Gleason pattern 4 is essential.

Updates on Grading and Staging of Prostate Cancer

Since its development between 1966 and 1977, the Gleason grading system has remained one of the most important prognostic indicators in prostatic acinar adenocarcinoma. The grading system was first majorly revised in 2005 and again in 2014. With the publication of the 8th edition of the American Joint Committee on Cancer TNM staging manual in 2018, the classification of prostate cancer and its reporting have further evolved and are now included as part of staging criteria. This article reflects the aspects that are most influential on daily practice. A brief summary of 3 ancillary commercially available genomic tests is also provided.

Large-Gland Proliferations of the Prostate

Large-gland proliferations of the prostate have gained considerable attention in the past decade. The differential diagnosis is quite broad but can be refined using histologic criteria and, sometimes, immunostains. Pathologists have come to realize that cribriform and intraductal as well as ductal carcinomas are particularly aggressive patterns, and should name them in diagnostic reporting when present.

Automatic Detection of Prostate Tumor Habitats using Diffusion MRI

A procedure for identification of optimal Apparent Diffusion Coefficient (ADC) thresholds for automatic delineation of prostatic lesions with restricted diffusion at differing risk for cancer was developed. The relationship between the size of the identified Volumes of Interest (VOIs) and Gleason Score (GS) was evaluated. Patients with multiparametric (mp)MRI, acquired prior to radical prostatectomy (RP) (n = 18), mpMRI-ultrasound fused (MRI-US) (n = 21) or template biopsies (n = 139) were analyzed. A search algorithm, spanning ADC thresholds in 50 µm²/s increments, determined VOIs that were matched to RP tumor nodules. Three ADC thresholds for both peripheral zone (PZ) and transition zone (TZ) were identified for estimation of VOIs at low, intermediate, and high risk of prostate cancer. The determined ADC thresholds for low, intermediate and high risk in PZ/TZ were: 900/800; 1100/850; and 1300/1050 µm²/s. The correlation coefficients between the size of the high/intermediate/low risk VOIs and GS in the three cohorts were 0.771/0.778/0.369, 0.561/0.457/0.355 and 0.423/0.441/0.36 (p < 0.05). Low risk VOIs mapped all RP lesions; area under the curve (AUC) for intermediate risk VOIs to discriminate GS6 vs GS ≥ 7 was 0.852; for high risk VOIs to discriminate GS6,7 vs GS ≥ 8 was 0.952. In conclusion, the automatically delineated volumes in the prostate with restricted diffusion were found to strongly correlate with cancer aggressiveness.

Correlation of mRNA-PCA3 urine levels with the new grading system in prostate cancer

PURPOSE

To evaluate the PCA3 (Prostate Cancer 3 gene) as a tool to improve prostate cancer (PCa) screening and its capability to predict PCa aggressiveness.

PATIENTS AND METHODS

A retrospective study with data from consecutive patients with suspected PCa seen in the urology department between November 2009 and April 2016 and who were candidates for prostate biopsy. A total of 1038 urine samples were tested in our laboratory with a kit that generated a PCA3 score (s-PCA3). A prostate biopsy was recommended only in those patients with s-PCA3≥35. Associations between variables were analyzed using the R software.

RESULTS

In patients with a positive s-PCA3 (44.5%), a subsequent biopsy was recommended. Of a total of 151 biopsies studied, 56.3% yielded a diagnosis of PCa. The probability of a positive biopsy increased as the s-PCA3 increased (p=0.041). The percentage of affected cylinders increased as the s-PCA3 increased (p=0.015). A statistically significant relationship was observed between s-PCA3 and both the Gleason score and the Grade Group (p=0.001 and 0.008, respectively). The best log-linear models and a logistic model confirmed the relationships shown previously with Fisher's exact tests.

CONCLUSIONS

S-PCA3 may serve as an additional marker to reduce the indication for biopsies and avoid overdiagnosis and overtreatment of patients with suspected PCa. The prognostic significance of s-PCA3 was confirmed, as it was associated with tumor volume and Gleason score. Importantly, to our knowledge this is the first time that an association has been demonstrated between s-PCA3 and the new Grade Group.

An Automated Multiparametric MRI Quantitative Imaging Prostate Habitat Risk Scoring System for Defining External Beam Radiation Therapy Boost Volumes

PURPOSE

To develop a prostate tumor habitat risk scoring (HRS) system based on multiparametric magnetic resonance imaging (mpMRI) referenced to prostatectomy Gleason score (GS) for automatic delineation of gross tumor volumes. A workflow for integration of HRS into radiation therapy boost volume dose escalation was developed in the framework of a phase 2 randomized clinical trial (BLaStM).

METHODS AND MATERIALS

An automated quantitative mpMRI-based 10-point pixel-by-pixel method was optimized to prostatectomy GSs and volumes using referenced dynamic contrast-enhanced and apparent diffusion coefficient sequences. The HRS contours were migrated to the planning computed tomography scan for boost volume generation.

RESULTS

There were 51 regions of interest in 12 patients who underwent radical prostatectomy (26 with GS ≥7 and 25 with GS 6). The resultant heat maps showed inter- and intratumoral heterogeneity. The HRS6 level was significantly associated with radical prostatectomy regions of interest (slope 1.09, r = 0.767; P < .0001). For predicting the likelihood of cancer, GS ≥7 and GS ≥8 HRS6 area under the curve was 0.718, 0.802, and 0.897, respectively. HRS was superior to the Prostate Imaging, Reporting and Diagnosis System 4/5 classification, wherein the area under the curve was 0.62, 0.64, and 0.617, respectively (difference with HR6, P < .0001). HRS maps were created for the first 37 assessable patients on the BLaStM trial. There were an average of 1.38 habitat boost volumes per patient at a total boost volume average of 3.6 cm³.

CONCLUSIONS

An automated quantitative mpMRI-based method was developed to objectively guide dose escalation to high-risk habitat volumes based on prostatectomy GS.

Multiparametric dynamic contrast-enhanced ultrasound imaging of prostate cancer

OBJECTIVES

The aim of this study is to improve the accuracy of dynamic contrast-enhanced ultrasound (DCE-US) for prostate cancer (PCa) localization by means of a multiparametric approach.

MATERIALS AND METHODS

Thirteen different parameters related to either perfusion or dispersion were extracted pixel-by-pixel from 45 DCE-US recordings in 19 patients referred for radical prostatectomy. Multiparametric maps were retrospectively produced using a Gaussian mixture model algorithm. These were subsequently evaluated on their pixel-wise performance in classifying 43 benign and 42 malignant histopathologically confirmed regions of interest, using a prostate-based leave-one-out procedure.

RESULTS

The combination of the spatiotemporal correlation (r), mean transit time (μ), curve skewness (κ), and peak time (PT) yielded an accuracy of 81% ± 11%, which was higher than the best performing single parameters: r (73%), μ (72%), and wash-in time (72%). The negative predictive value increased to 83% ± 16% from 70%, 69% and 67%, respectively. Pixel inclusion based on the confidence level boosted these measures to 90% with half of the pixels excluded, but without disregarding any prostate or region.

CONCLUSIONS

Our results suggest multiparametric DCE-US analysis might be a useful diagnostic tool for PCa, possibly supporting future targeting of biopsies or therapy. Application in other types of cancer can also be foreseen.

KEY POINTS

• DCE-US can be used to extract both perfusion and dispersion-related parameters. • Multiparametric DCE-US performs better in detecting PCa than single-parametric DCE-US. • Multiparametric DCE-US might become a useful tool for PCa localization.

Clinical significance of endothelial cell marker CD34 and mast cell marker CD117 in prostate adenocarcinoma

Prostate cancer is the second cause of cancer-related deaths in men and this is attributed to its aggressiveness and metastatic identity. Our objective was to evaluate the expression patterns of endothelial cell marker CD34 and mast cell marker CD117 in prostate adenocarcinoma (PCa) compared to benign prostate tissue and their relation to the clinicopathological features. A total of 90 prostate samples, including 45 PCa and 45 benign prostate tissues were immunohistochemically examined for the detection of CD34 and CD117 markers. The expression of these markers was also correlated with clinicopathological parameters. Significant overexpression of CD34 was found in PCa group compared to benign prostate tissues (P≤0.001). The expression of CD34 and CD117 in PCa with advanced Gleason score was more than PCa with early Gleason score (P=0.02 and P=0.005, respectively). A significant positive correlation was observed between CD34 expression and the level of total serum prostate specific antigen (sPSA) (P=0.006). In addition, CD34High/CD117High phenotype was frequently observed in PCa cases compared to benign prostate tissues (P≤0.001). There was a positive significant association between CD34High/CD117High phenotype with advanced Gleason score (P≤0.001) and total sPSA level (P=0.02). Our findings showed that increased expression of CD34 and CD117 markers confer tumor progression and aggressiveness on PCa. These molecules may be good candidates for targeted therapy of PCa patients.

North American Population-Based Validation of the National Comprehensive Cancer Network Practice Guideline Recommendation of Pelvic Lymphadenectomy in Contemporary Prostate Cancer

BACKGROUND

National Comprehensive Cancer Network (NCCN) guidelines recommend a pelvic lymph node dissection (PLND) in prostate cancer (PCa) patients treated with radical prostatectomy (RP) if a nomogram predicted risk of lymph node invasion (LNI) is ≥2%. We examined this and other thresholds, including nomogram validation.

METHODS

We examined records of 26,713 patients treated with RP and PLND between 2010 and 2013, within the Surveillance, Epidemiology, and End Results database. Nomogram thresholds of 2-5% were tested and external validation was performed.

RESULTS

LNI was recorded in 4.7% of patients. Nomogram accuracy was 80.4% and maintained minimum accuracy of 75.6% in subgroup analyses, according to age, race, and nodal yield >10. With the NCCN recommended 2% nomogram threshold, PLND could be avoided in 22.3% of patients at the expense of missing 3.0% of individuals with LNI. Alternative thresholds of 3%, 4%, and 5% yielded respective PLND avoidance rates of 60.4%, 71.0%, and 79.8% at the expense of missing 17.8%, 27.2%, and 36.6% of patients with LNI. NCCN cut-off recommendation was best satisfied with a threshold of <2.6%, at which PLND could be avoided in 13,234 patients (49.5%) versus missing 141 patients with LNI (11.2%).

CONCLUSION

NCCN LNI nomogram remains accurate in contemporary patients. However, the 2% threshold appears to be too strict, since only 22.3% of PLNDs can be avoided, instead of the stipulated 47.7%. The optimal 2.6% threshold allows a higher rate of PLND avoidance (49.5%), at the cost of 11.2% missed instances of LNI, as recommended by NCCN guidelines. PATIENT SUMMARY. External validation in contemporary SEER prostate cancer patients showed that the NCCN nomogram remains accurate for predicting lymph node invasion and seems to be optimal at an alternative 2.6% threshold, with best ratio of avoided pelvic lymph node dissections (49.5%) and missed LNIs (11.2%), as recommended by NCCN guideline. Prostate 77:542-548, 2017. © 2017 Wiley Periodicals, Inc.

Difluoromethylornithine in cancer: new advances

Difluoromethylornithine (DFMO; eflornithine) is an irreversible suicide inhibitor of the enzyme ornithine decarboxylase which is involved in polyamine synthesis. Polyamines are important for cell survival, thus DFMO was studied as an anticancer agent and as a chemoprevention agent. DFMO exhibited mainly cytostatic activity and had single agent efficacy as well as activity in combination with other chemotherapeutic drugs for some cancers and leukemias. Herewith, we summarize the current knowledge of the anticancer and chemopreventive properties of DFMO and assess the status of clinical trials.

The Importance of Histology and Pathology in Mass Spectrometry Imaging

Mass spectrometry imaging (MSI) has become a valuable tool in cancer research. Even more, due to its capability to directly link molecular changes with histology, it holds the prospect to revolutionize tissue-based diagnostics. In order to learn to walk before running, however, information obtained through classical histology should not be neglected but rather used to its full capacity and integrated with mass spectrometry data to lead to a superior molecular histology synthesis. In order to achieve this, pathomorphological analyses have to be integrated into MSI analyses right from the beginning to avoid errors and pitfalls of MSI application possibly leading to incorrect or imprecise study outcomes. Such errors can be caused by different sample or tissue inherent factors or through factors in sample preparation. Future studies should, therefore, aim for a comprehensive incorporation of histology and pathology characteristics to ensure the generation of high-quality data in MSI to exploit its full capacity in tissue-based basic and translational research.

Molecular mechanisms underlying resistance to androgen deprivation therapy in prostate cancer

Prostate cancer (PCa) is the most widely diagnosed male cancer in the Western World and while low- and intermediate-risk PCa patients have a variety of treatment options, metastatic patients are limited to androgen deprivation therapy (ADT). This treatment paradigm has been in place for 75 years due to the unique role of androgens in promoting growth of prostatic epithelial cells via the transcription factor androgen receptor (AR) and downstream signaling pathways. Within 2 to 3 years of ADT, disease recurs-at which time, patients are considered to have castration-recurrent PCa (CR-PCa). A universal mechanism by which PCa becomes resistant to ADT has yet to be discovered. In this review article, we discuss underlying molecular mechanisms by which PCa evades ADT. Several major resistance pathways center on androgen signaling, including intratumoral and adrenal androgen production, AR-overexpression and amplification, expression of AR mutants, and constitutively-active AR splice variants. Other ADT resistance mechanisms, including activation of glucocorticoid receptor and impairment of DNA repair pathways are also discussed. New therapies have been approved for treatment of CR-PCa, but increase median survival by only 2-8 months. We discuss possible mechanisms of resistance to these new ADT agents. Finally, the practicality of the application of "precision oncology" to this continuing challenge of therapy resistance in metastatic or CR-PCa is examined. Empirical validation and clinical-based evidence are definitely needed to prove the superiority of "precision" treatment in providing a more targeted approach and curative therapies over the existing practices that are based on biological "cause-and-effect" relationship.

Prostate cancer outcomes of men with biopsy Gleason score 6 and 7 without cribriform or intraductal carcinoma

AIM OF THE STUDY

Gleason score (GS) 3 + 4 = 7 prostate cancer patients with presence of cribriform or intraductal carcinoma (7(+)) have a worse disease-specific survival than those without. The aim of this study was to compare the clinicopathologic characteristics and patient outcomes of men with biopsy GS 3 + 4 = 7 without cribriform or intraductal carcinoma (7(-)) to those with GS 3 + 3 = 6.

MATERIALS AND METHODS

We included all patients from the first screening round of the European Randomized Study of Screening for Prostate Cancer (1993-2000) with a revised GS ≤ 3 + 4 = 7 (n = 796) following the 2014 International Society of Urological Pathology criteria. Relations with biochemical recurrence after radical prostatectomy or radiotherapy were analysed using log-rank testing and multivariable Cox regression analysis.

RESULTS

In total, 486 patients had GS 6 and 310 had GS 7, 54 of whom had GS 7(+) (17%). During a median follow-up of 15 years, biochemical recurrence was seen in 61 (20%) GS 6, 54 (21%) GS 7(-) and 22 (41%) GS 7(+) patients (41%). Both biopsy GS 7(-) and 7(+) patients had significantly higher prostate-specific antigen levels, mean tumour percentage, percentage of positive cores and ≥cT3 than those with GS 6 (all P < .001). GS 7(-) patients did not have a poorer biochemical recurrence-free survival (BCRFS) after radical prostatectomy than GS 6 patients (log-rank P = .13), whereas those with GS 7(+) had (log-rank P = .05). In multivariable analyses, biopsy GS 7(-) was not associated with poorer BCRFS after radical prostatectomy (hazard ratio [HR], 1.3; 95% confidence interval [CI]: 0.67-2.4; P = .47) or radiotherapy (HR, 0.88; 95% CI: 0.51-1.5; P = .63). GS 7(+) was independently associated with poorer BCRFS after radical prostatectomy (HR, 3.0; 95% CI: 1.1-7.8; P = .03), but not after radiotherapy (HR, 1.2; 95% CI: 0.58-2.3; P = .67).

CONCLUSIONS

Men with biopsy GS 7(-) prostate cancer have similar BCRFS after radical prostatectomy or radiotherapy to those with GS 6 and may be candidates for active surveillance as long as other inclusion criteria such as on PSA and tumour volume are met.

Outcome of Gleason 3 + 5 = 8 Prostate Cancer Diagnosed on Needle Biopsy: Prognostic Comparison with Gleason 4 + 4 = 8

PURPOSE

ISUP (International Society for Urologic Pathology) and WHO adopted prognostic Grade Groups 1 to 5 that simplify prostate cancer grading for prognosis. Grade Group 4 is Gleason score 8 cancer, which is heterogeneous, and it encompasses Gleason score 4 + 4 = 8, 3 + 5 = 8 and 5 + 3 = 8. The comparative prognostic implications of these various Gleason scores had not been studied by urological pathologists after a re-review of slides.

MATERIALS AND METHODS

Patients with a highest biopsy Gleason score of 3 + 5 = 8 or 4 + 4 = 8 were included in the study. Controls were cases with a highest Gleason score of 4 + 3 = 7 or 9-10. A total of 423 prostatic biopsy cases accessioned from 2005 to 2013 at 2 institutions were reviewed. Clinicopathological findings and followup (median 33.4 months) were assessed.

RESULTS

Among Gleason score 8 cancers the cancer status outcome in 51 men with Gleason score 3 + 5 = 8 was marginally worse than in 114 with Gleason score 4 + 4 = 8 (p = 0.04). This was driven by a persistent nonmetastatic (after radiation/hormone therapy) cancer rate of 37% among Gleason score 3 + 5 = 8 cases vs 24% among Gleason score 4 + 4 = 8 cases. Conversely, cancer specific survival at 36-month followup was 97.8% in 3 + 5 cases vs 92.6% in 4 + 4 cases but this was not significant (p = 0.089). Cancer specific survival in the Gleason score 8 group was dichotomized by the presence of cribriform growth (p = 0.018). All Gleason score categories did not differ in the fraction of biopsy cores positive, clinical presentation or pathological findings, including the frequency of Gleason pattern 5, in 70 patients who underwent prostatectomy.

CONCLUSIONS

Using the most current standards of prostate cancer grading the prognosis is not different in Gleason score 3 + 5 = 8 and 4 + 4 = 8 cancers. This justifies including both in Grade Group 4.

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.