The CONFIRM trial protocol: the utility of prostate-specific membrane antigen positron emission tomography/computed tomography in active surveillance for prostate cancer.

OBJECTIVES: Primary objectives: To determine the additive value of prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) in the risk stratification of men with newly diagnosed prostate cancer (PCa) who would have otherwise been deemed suitable for active surveillance (AS). Specifically, we aim to determine if PSMA PET/CT can detect a cohort of men on AS that are in fact high risk and likely to experience unfavourable outcomes should they remain on their current treatment pathway. SECONDARY OBJECTIVES: to determine the additive value of PSMA PET/CT to repeat multiparametric magnetic resonance imaging (mpMRI) of the prostate and explore whether a confirmatory biopsy may be avoided in men with a negative PSMA PET/CT and a negative repeat mpMRI of the prostate (Prostate Imaging-Reporting and Data System score of <3). Furthermore, to develop a nomogram combining clinical, imaging and biomarker data to predict the likelihood of failure on AS in men with high-risk features. Also, a blood sample will be taken to perform a Prostate Health Index test at the time of confirmatory biopsy. Furthermore, a portion of this blood will be stored at a biobank for up to 5 years if a follow-up study on molecular biomarkers and genetic assays in this cohort of men is indicated, based on the results from the CONFIRM trial. PATIENTS AND METHODS: The CONFIRM trial is a prospective, multicentre, pre-test/post-test, cohort study across Victoria, Australia, involving men with newly diagnosed low-risk PCa with high-risk features, considered suitable for AS and undergoing confirmatory biopsy. The trial's goal is to provide high-quality evidence to establish whether PSMA PET/CT has a role in risk-stratifying men deemed suitable for AS despite having high-risk feature(s). RESULTS: The CONFIRM trial will measure the proportion of men deemed unsuitable for ongoing AS based on pathological upgrading and multidisciplinary team recommendation due to PSMA PET/CT scan and PSMA-targeted confirmatory biopsy. Additionally, the positive and negative predictive values, sensitivity, and specificity of PSMA PET/CT will be calculated in isolation and combined with repeat mpMRI of the prostate. CONCLUSIONS: This trial will provide robust prospective data to determine if PSMA-PET/CT and standard of care (prostate biopsy ± repeat mpMRI) can improve diagnostic certainty in men undergoing confirmatory biopsy for low-grade PCa with high-risk features.

The MURAL collection of prostate cancer patient-derived xenografts enables discovery through preclinical models of uro-oncology.

Preclinical testing is a crucial step in evaluating cancer therapeutics. We aimed to establish a significant resource of patient-derived xenografts (PDXs) of prostate cancer for rapid and systematic evaluation of candidate therapies. The PDX collection comprises 59 tumors collected from 30 patients between 2012-2020, coinciding with availability of abiraterone and enzalutamide. The PDXs represent the clinico-pathological and genomic spectrum of prostate cancer, from treatment-naïve primary tumors to castration-resistant metastases. Inter- and intra-tumor heterogeneity in adenocarcinoma and neuroendocrine phenotypes is evident from bulk and single-cell RNA sequencing data. Organoids can be cultured from PDXs, providing further capabilities for preclinical studies. Using a 1 x 1 x 1 design, we rapidly identify tumors with exceptional responses to combination treatments. To govern the distribution of PDXs, we formed the Melbourne Urological Research Alliance (MURAL). This PDX collection is a substantial resource, expanding the capacity to test and prioritize effective treatments for prospective clinical trials in prostate cancer.

Ductal variant prostate carcinoma is associated with a significantly shorter metastasis-free survival.

BACKGROUND: Ductal adenocarcinoma is an uncommon prostate cancer variant. Previous studies suggest that ductal variant histology may be associated with worse clinical outcomes, but these are difficult to interpret. To address this, we performed an international, multi-institutional study to describe the characteristics of ductal adenocarcinoma, particularly focussing on the effect of presence of ductal variant cancer on metastasis-free survival. METHODS: Patients with ductal variant histology from two institutional databases who underwent radical prostatectomies were identified and compared with an independent acinar adenocarcinoma cohort. After propensity score matching, the effect of the presence of ductal adenocarcinoma on time to biochemical recurrence, initiation of salvage therapy and the development of metastatic disease was determined. Deep whole-exome sequencing was performed for selected cases (n = 8). RESULTS: A total of 202 ductal adenocarcinoma and 2037 acinar adenocarcinoma cases were analysed. Survival analysis after matching demonstrated that patients with ductal variant histology had shorter salvage-free survival (8.1 versus 22.0 months, p = 0.03) and metastasis-free survival (6.7 versus 78.6 months, p < 0.0001). Ductal variant histology was consistently associated with RB1 loss, as well as copy number gains in TAP1, SLC4A2 and EHHADH. CONCLUSIONS: The presence of any ductal variant adenocarcinoma at the time of prostatectomy portends a worse clinical outcome than pure acinar cancers, with significantly shorter times to initiation of salvage therapies and the onset of metastatic disease. These features appear to be driven by uncoupling of chromosomal duplication from cell division, resulting in widespread copy number aberration with specific gain of genes implicated in treatment resistance.

Patient-derived Models of Abiraterone- and Enzalutamide-resistant Prostate Cancer Reveal Sensitivity to Ribosome-directed Therapy.

BACKGROUND: The intractability of castration-resistant prostate cancer (CRPC) is exacerbated by tumour heterogeneity, including diverse alterations to the androgen receptor (AR) axis and AR-independent phenotypes. The availability of additional models encompassing this heterogeneity would facilitate the identification of more effective therapies for CRPC. OBJECTIVE: To discover therapeutic strategies by exploiting patient-derived models that exemplify the heterogeneity of CRPC. DESIGN, SETTING, AND PARTICIPANTS: Four new patient-derived xenografts (PDXs) were established from independent metastases of two patients and characterised using integrative genomics. A panel of rationally selected drugs was tested using an innovative ex vivo PDX culture system. INTERVENTION: The following drugs were evaluated: AR signalling inhibitors (enzalutamide and galeterone), a PARP inhibitor (talazoparib), a chemotherapeutic (cisplatin), a CDK4/6 inhibitor (ribociclib), bromodomain and extraterminal (BET) protein inhibitors (iBET151 and JQ1), and inhibitors of ribosome biogenesis/function (RNA polymerase I inhibitor CX-5461 and pan-PIM kinase inhibitor CX-6258). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Drug efficacy in ex vivo cultures of PDX tissues was evaluated using immunohistochemistry for Ki67 and cleaved caspase-3 levels. Candidate drugs were also tested for antitumour efficacy in vivo, with tumour volume being the primary endpoint. Two-tailed t tests were used to compare drug and control treatments. RESULTS AND LIMITATIONS: Integrative genomics revealed that the new PDXs exhibited heterogeneous mechanisms of resistance, including known and novel AR mutations, genomic structural rearrangements of the AR gene, and a neuroendocrine-like AR-null phenotype. Despite their heterogeneity, all models were sensitive to the combination of ribosome-targeting agents CX-5461 and CX-6258. CONCLUSIONS: This study demonstrates that ribosome-targeting drugs may be effective against diverse CRPC subtypes including AR-null disease, and highlights the potential of contemporary patient-derived models to prioritise treatment strategies for clinical translation. PATIENT SUMMARY: Diverse types of therapy-resistant prostate cancers are sensitive to a new combination of drugs that inhibit protein synthesis pathways in cancer cells.

Multiparametric magnetic resonance imaging for prostate cancer-a comparative study including radical prostatectomy specimens.

PURPOSE: To evaluate the diagnostic and staging ability of multiparametric MRI (mpMRI) compared to radical prostatectomy (RP) specimens after dissemination of this technology to several centres. mpMRI is an evolving technique aiming to improve upon the diagnostic sensitivity of prostate biopsy for the diagnosis of prostate cancer. Differences in interpretation, expertise and application of mpMRI are responsible for the range of reported results. METHODS: This retrospective clinical study was conducted with consecutive patients through an electronic database of tertiary hospitals and adjacent private urology practices in Australia. Patients having undergone RP were assessed for the presence of a pre-operative mpMRI performed between 2013 and 2015 which was evaluated against the reference standard of the RP whole-mount specimen. MRI reports were evaluated using the Prostate Imaging Reporting and Data System (PI-RADS). RESULTS: In our cohort of 152 patients, the sensitivity and specificity of mpMRI (PI-RADS ≥ 4) for prostate cancer (Gleason ≥ 4 + 3) detection were 83 and 47%, respectively. For the identification of extraprostatic disease, the sensitivity and specificity were 29 and 94%, respectively. CONCLUSION: These results represent a 'real-world' approach to mpMRI and appear comparable to other single-centre studies. MRI staging information should be interpreted in context with other risk factors for extraprostatic disease. mpMRI has a useful role as an adjunct for prostate cancer diagnosis and directing management towards improving patient outcomes.

Reduction in expression of the benign AR transcriptome is a hallmark of localised prostate cancer progression.

BACKGROUND: Despite the importance of androgen receptor (AR) signalling to prostate cancer development, little is known about how this signalling pathway changes with increasing grade and stage of the disease. OBJECTIVE: To explore changes in the normal AR transcriptome in localised prostate cancer, and its relation to adverse pathological features and disease recurrence. DESIGN: Publically accessible human prostate cancer expression arrays as well as RNA sequencing data from the prostate TCGA. Tumour associated PSA and PSAD were calculated for a large cohort of men (n=1108) undergoing prostatectomy. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We performed a meta-analysis of the expression of an androgen-regulated gene set across datasets using Oncomine. Differential expression of selected genes in the prostate TCGA database was probed using the edgeR Bioconductor package. Changes in tumour PSA density with stage and grade were assessed by Student's t-test, and its association with biochemical recurrence explored by Kaplan-Meier curves and Cox regression. RESULTS: Meta-analysis revealed a systematic decline in the expression of a previously identified benign prostate androgen-regulated gene set with increasing tumour grade, reaching significance in nine of 25 genes tested despite increasing AR expression. These results were confirmed in a large independent dataset from the TCGA. At the protein level, when serum PSA was corrected for tumour volume, significantly lower levels were observed with increasing tumour grade and stage, and predicted disease recurrence. CONCLUSIONS: Lower PSA secretion-per-tumour-volume is associated with increasing grade and stage of prostate cancer, has prognostic relevance, and reflects a systematic perturbation of androgen signalling.

Does perineural invasion in a radical prostatectomy specimen predict biochemical recurrence in men with prostate cancer?

INTRODUCTION: The ability of perineural invasion (PNI) in radical prostatectomy (RP) specimens to predict biochemical recurrence (BCR) is unclear. This study investigates this controversial question in a large cohort. METHODS: A retrospective analysis was undertaken of prospectively collected data from 1497 men who underwent RP (no neoadjuvant therapy) for clinically localized prostate cancer. The association of PNI at RP with other clinicopathological parameters was evaluated. The correlation of clinicopathological factors and BCR (defined as prostate-specific antigen [PSA] >0.2 ng/mL) was investigated with univariable and multivariable Cox regression analysis in 1159 men. RESULTS: PNI-positive patients were significantly more likely to have a higher RP Gleason score, pT3 disease, positive surgical margins, and greater cancer volume (p < 0.0005). The presence of PNI significantly correlated with BCR on univariable (hazard ratio 2.30, 95% confidence interval 1.50-3.55, p < 0.0005), but not multivariable analysis (p = 0.602). On multivariable Cox regression analysis the only independent prognostic factors were preoperative PSA, RP Gleason score, pT-stage, and positive surgical margin status. These findings are limited by a relatively short follow-up time and retrospective study design. CONCLUSIONS: PNI at RP is not an independent predictor of BCR. Therefore, routine reporting of PNI is not indicated. Future research should be targeted at the biology of PNI to increase the understanding of its role in prostate cancer progression.

Presence or absence of a positive pathological margin outperforms any other margin-associated variable in predicting clinically relevant biochemical recurrence in Gleason 7 prostate cancer.

UNLABELLED: WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: The presence of a positive pathological margin is an independent risk factor for clinically significant disease recurrence only in intermediate-risk disease when the a priori risk of micrometastatic disease is accounted for. The study examines patients with Gleason 7 prostate cancer to assess the relative importance of various margin-related variables (focality, linear length, tumour grade at margin, presence of diathermy artifact and plane of tumour) with regard to biochemical recurrence. We found that the presence or absence of a positive pathological margin outperforms any other margin-associated variable in predicting significant disease recurrence. OBJECTIVE: To determine the influence of pathological margin variables on the risk of clinically significant biochemical recurrence in Gleason 7 prostate cancer. MATERIALS AND METHODS: Patients with Gleason 7 prostate cancer with complete clinical and pathological data and detailed follow-up were identified from a prospectively recorded prostatectomy database. Slides from all patients with positive pathological margins were reviewed by a single expert uropathologist and the following information recorded: multifocality, linear length, predominant Gleason grade at the margin, diathermy artifact and margin plane. Cox regression models were generated to determine the impact of positive pathological margins on the risk of biochemical recurrence (using various definitions thereof). RESULTS: Of 1048 patients with Gleason 7 prostate cancer, 238 (23%) patients had positive margins. With a median follow-up of 11 months, biochemical recurrence occurred in 9.7% of patients with negative surgical margins and 28.4% of patients with positive margins. Positive margins were significantly associated with higher serum prostate-specific antigen (PSA) level, tumour grade, stage and volume. In patients with positive pathological margins, controlling for other factors, no margin-derived variable (focality, linear length, tumour grade at margin, diathermy artifact or plane of tumour) was a consistent predictor of biochemical recurrence, although the presence of Gleason score 4 or tertiary Gleason score 5 tumour at the margin edge was an independent predictor of recurrence with PSA doubling times ≤ 6 and ≤9 months. Similarly, in the cohort as a whole, the pathological margin status was a more important predictor of recurrence than any other margin-derived variable. CONCLUSIONS: In Gleason 7 prostate cancer, positive pathological margin status was the only consistent margin-derived variable determining biochemical failure. The presence of high-grade disease at the margin may also have an impact on the development of clinically significant biochemical recurrence.

Re-evaluating the biological significance of seminal vesicle invasion (SVI) in locally advanced prostate cancer.

OBJECTIVE: • To examine the impact of seminal vesicle invasion (SVI) in patients with locally advanced (pT3) prostate cancer on clinical outcome. • To explore the clinical association of SVI with metastatic disease. • To distinguish between the possibilities that either seminal vesicles possess their own biological significance and represent a privileged staging site for systemic tumour cell dissemination, or that their invasion is a surrogate marker for an aggressive large-volume poorly differentiated cancer. PATIENTS AND METHODS: • Patients with extraprostatic extension (EPE) and/or SVI were identified from a prospectively recorded and maintained prostate cancer database. • Patients were categorised according to the presence of SVI as determined by routine pathological assessment. Tumour volumes were measured routinely by computed planimetry at the time of histological assessment. • The impact of SVI on biochemical recurrence with a definition of a prostate-specific antigen (PSA) level of ≥0.2 ng/mL, as well as a clinically significant recurrence defined as failure with a PSA doubling time of <6 months, was determined by univariable and multivariable Cox regression analysis. RESULTS: • Of 249 patients with pT3 disease, 46 (18%) had SVI, 40 (87%) by direct extension and six (13%) metastatic. • Tumours with SVI had significantly greater tumour burden as determined by total tumour volume (7.2 vs 3.7 mL, P < 0.001), index tumour volume (6.8 vs. 3.4 mL, P < 0.001) and percentage tumour volume (21.8 vs 12.4 %, P= 0.001). • After controlling for tumour volume and Gleason score, the presence of SVI did not significantly predict for the development of a significant PSA recurrence. CONCLUSIONS: • Our results suggest that SVI is a surrogate marker of larger and more aggressive tumours with higher Gleason scores rather than a privileged site of tumour cell dissemination.

Utility of RhoC and ZAG protein expression as biomarkers for prediction of PSA failure following radical prostatectomy for high grade prostate cancer.

AIMS: To assess the prognostic utility of semi-quantiative expression of RhoC protein in whole prostates from patients who had radical prostatectomies for high grade prostate cancer (PCa). METHODS: Subjects who had surgery >55 months previously with primary Gleason pattern 4 PCa were identified from practice records, archival tissues were retrieved for review and RhoC immunohistochemistry, and ZAG expression was also assessed as a control. RESULTS: Eighty-nine subjects were included in the study; 57 had a rising prostate specific antigen (PSA) post-operatively ('cases') and 32 did not ('controls'). By univariate analysis, expression of both RhoC and ZAG proteins was greater in controls than cases, but this was significant only for ZAG. By multivariate analysis, Gleason variables (patterns and score), extraprostatic extension and decreased RhoC staining all contributed to predicting PSA failure (p < 0.05). ZAG expression was inversely correlated with Gleason pattern and hence was not independently predictive in our multivariate model. CONCLUSIONS: Increased RhoC expression predicted a good outcome after radical prostatectomy. ZAG staining also correlated with a favourable outcome but was not independently predictive due to its relationship with Gleason pattern.

Human epithelial basal cells are cells of origin of prostate cancer, independent of CD133 status.

Normal prostatic epithelium is composed of basal and luminal cells. Prostate cancer can be initiated in both benign basal and luminal stem cells, but because basal cell markers are not expressed in patient tumors, the former result was unexpected. Since the cells of origin of prostate cancer are important therapeutic targets, we sought to provide further proof that basal stem cells have tumorigenic potential. Prostatic basal cells were enriched based on α2ß1integrin(hi) expression and further enriched for stem cells using CD133 in nontumorigenic BPH-1 cells. Human embryonic stem cells (hESCs) were also used as a source of normal stem cells. To test their tumorigenicity, we used two alternate stromal-based approaches; (a) recombination with human cancer-associated fibroblasts (CAFs) or (b) recombination with embryonic stroma (urogenital mesenchyme) and treated host mice with testosterone and 17ß-estradiol. Enriched α2ß1integrin(hi) basal cells from BPH-1 cells resulted in malignant tumor formation using both assays of tumorigenicity. Surprisingly, the tumorigenic potential did not reside in the CD133(+) stem cells but was consistently observed in the CD133(-) population. CAFs also failed to induce prostatic tumors from hESCs. These data confirmed that benign human basal cells include cells of origin of prostate cancer and reinforced their importance as therapeutic targets. In addition, our data suggested that the more proliferative CD133(-) basal cells are more susceptible to tumorigenesis compared to the CD133(+)-enriched stem cells. These findings challenge the current dogma that normal stem cells and cells of origin of cancer are the same cell type(s).

Positive surgical margins are a risk factor for significant biochemical recurrence only in intermediate-risk disease.

UNLABELLED: What's known on the subject? and What does the study add? Positive surgical margins (PSMs) after radical prostatectomy are common, although their impact on the risk of disease recurrence is unknown. We examined the impact of PSMs on the risk of 'significant' biochemical recurrence stratified by their risk of occult metastatic disease. We find that only in intermediate-risk disease does the presence of a PSM have a significant impact on the risk of recurrence, and this represents a failure of technique. By contrast, for high- and low-risk disease, the risk of recurrence is driven by intrinsic tumour biology, and the presence of a PSM has little impact on outcome. OBJECTIVE: To determine the impact of surgical margin status on the risk of significant biochemical recurrence (prostate-specific antigen [PSA] doubling time <3, <6 or <9 months) after prostatectomy. MATERIALS AND METHODS: Patients undergoing radical prostatectomy with complete clinical and pathological data and detailed PSA follow-up were identified from two prospectively recorded databases. Patients were stratified according to their risk of occult systemic disease (low risk: PSA < 10 ng/dL, pT2 stage and Gleason score ≤6; intermediate risk: PSA 10-20 ng/dL, pT2 stage and/or Gleason score 7; high: PSA > 20 ng/dL or pT3-4 stage or Gleason score 8-10) and the impact of a positive surgical margin (PSM) within each stratum determined by univariable and multivariable analysis. RESULTS: Of 1514 patients identified, 276 (18.2%), 761 (50.3%) and 477 (31.5%) were classified as having low-, intermediate- and high-risk disease respectively. A total of 370 (24.4%) patients had a PSM and with a median follow-up of 22.2 months, and 165 (7%) patients had a biochemical recurrence. Sufficient PSA data was available to calculate PSA doubling times in 151/165 patients (91.5%). The PSM rate rose significantly, from 11% in low-risk to 43% in high-risk disease (P < 0.001), with similar positive associations noted with tumour grade, stage and serum PSA (P < 0.001). Patients with low-risk disease had essentially identical risks of significant biochemical recurrence over the study period, regardless of surgical margin status. By contrast, in patients with both intermediate- and high-risk disease, a PSM was a strong predictor of significant biochemical recurrence on univariable analysis. On multivariable analysis, howver, PSM predicted significant disease recurrence in intermediate-risk disease only. CONCLUSIONS: PSM is a risk factor for significant biochemical recurrence only in intermediate risk disease.

The ability of prostate-specific antigen (PSA) density to predict an upgrade in Gleason score between initial prostate biopsy and prostatectomy diminishes with increasing tumour grade due to reduced PSA secretion per unit tumour volume.

UNLABELLED: Study Type - Diagnostic (exploratory cohort) Level of Evidence 2b What's known on the subject? and What does the study add? Due to sampling error, the Gleason score of clinically localized prostate cancer is frequently underestimated at the time of initial biopsy. Given that this may lead to inappropriate surveillance of patients with high-risk disease, there is considerable interest in identifying predictors of significant undergrading. Recently PSAD has been proposed to be an accurate predictor of subsequent upgrading in patients diagnosed with Gleason 6 disease on biopsy. We examined the predictive characteristics of PSAD in patients with low- and intermediate-risk disease on biopsy subsequently treated with radical prostatectomy. We found that although PSAD was a significant predictor of upgrade of biopsy Gleason 6 and 3 + 4 = 7 tumours, it failed to predict upgrading in patients with Gleason 7 tumours taken as a whole. When we explored reasons for this discrepancy, we found that the amount of PSA produced per unit tumour volume decreased with increasing Gleason score, thereby diminishing the predictive value of PSAD. OBJECTIVES: To analyse the performance of PSA density (PSAD) as a predictor of Gleason score upgrade in a large cohort stratified by Gleason score. We and others have shown that an upgrade in Gleason score between initial prostate biopsy and final radical prostatectomy (RP) pathology is a significant risk factor for recurrence after local therapy. PATIENTS AND METHODS: Patients undergoing RP with matching biopsy information were identified from two prospective databases. Patients were analysed according to the concordance between biopsy and final pathology Gleason score in three paired groups: 6/>6, 3 + 4/>3 + 4, 7/>7. Receiver-operating characteristic (ROC) curves were generated stratified by Gleason score, and the area under the curve (AUC) calculated. Logistic regression models were fitted to identify significant predictors of tumour upgrade. RESULTS: From 1516 patients, 435 (29%) had an upgrade in Gleason score. ROC analysis showed a decline in AUC with increasing biopsy Gleason score, from 0.64 for biopsy Gleason score 6, to 0.57 for Gleason score 7. In logistic regression models containing pretreatment variables, e.g. clinical stage and number of positive cores, for Gleason score 6 and 3 + 4, PSAD was the strongest predictor of subsequent tumour upgrade (odds ratio [OR] 1.46, 95% confidence interval [95% CI] 1.18-1.83, P= 0.001 and OR 1.37, 95% CI 1.14-1.67, P= 0.002, respectively). Surprisingly, in tumours upgraded from Gleason score 7 to >7, PSAD was not predictive even on univariable analysis, whereas clinical stage and number of positive cores were significant independent predictors. To explore the relationship between serum PSA and Gleason score, tumour volume was calculated in 669 patients. There was a strong association between Gleason score and tumour volume, with the median volume of Gleason score 7 and Gleason score >7 tumours being approximately twice and four-times that of Gleason score 6 tumours, respectively (P < 0.001). In contrast, the median serum PSA level per millilitre tumour volume decreased significantly with increasing grade, from 5.4 ng/mL for Gleason score 6 to 2.1 ng/mL for >7 (P < 0.001). CONCLUSIONS: There is a strong correlation between Gleason score and tumour volume in well/intermediate differentiated tumours, and as they produce relatively high amounts of PSA per unit volume of cancer, high PSAD is the strongest single predictor of tumour undergrading. However, as higher grade tumours produce less PSA per unit volume, PSAD loses its predictive ability, and other clinical markers of tumour volume such as palpable disease and numbers of positive cores become more predictive.

Underestimation of Gleason score at prostate biopsy reflects sampling error in lower volume tumours.

OBJECTIVE: • To determine the influence of tumour and prostate gland volumes on the underestimation of prostate cancer Gleason score in diagnostic core biopsies. PATIENTS AND METHODS: • Patients undergoing radical prostatectomy with matched diagnostic biopsies were identified from a prospectively recorded database. • Tumour volumes were measured in serial whole-mount sections with image analysis software as part of routine histological assessment. • Differences in various metrics of tumour and prostate volume between upgraded tumours and tumours concordant for the lower or higher grade were analysed. RESULTS: • In all, 684 consecutive patients with Gleason score 6 or 7 prostate cancer on diagnostic biopsy were identified. • Of 298 patients diagnosed with Gleason 6 tumour on biopsy, 201 (67.4%) were upgraded to Gleason 7 or higher on final pathology. Similarly, of 262 patients diagnosed with Gleason 3 + 4 = 7 prostate cancer on initial biopsy, 60 (22.9%) were upgraded to Gleason score 4 + 3 = 7 or higher. • Tumours upgraded from Gleason 6 to 7 had a significantly lower index tumour volume (1.73 vs 2 mL, P= 0.029), higher calculated prostate volume (41.6 vs 39 mL, P= 0.017) and lower relative percentage of tumour to benign glandular tissue (4.3% vs 5.9%, P= 0.001) than tumours concordant for the higher grade. • Similarly, tumours that were Gleason score 3 + 4 on biopsy and upgraded on final pathology to 4 + 3 were significantly smaller as measured by both total tumour volume (2.3 vs 3.3 mL, P= 0.005) and index tumour volume (2.2 vs 3, P= 0.027) and occupied a smaller percentage of the gland volume (6.3% vs 8.9%, P= 0.017) compared with tumours concordant for the higher grade. • On multivariate analysis, lower prostate weight (hazard ratio 0.97, 95% confidence interval 0.96-0.99, P < 0.001) and larger total tumour volume (hazard ratio 1.87, 95% confidence interval 1.4-2.6, P < 0.001) independently predicted an upgrade in Gleason score from 6 to 7. In tumours upgraded from biopsy Gleason 3 + 4, only higher index tumour volume (hazard ratio 3.1, 95% confidence interval 1.01-9.3, P= 0.048) was a significant predictor of upgrading on multivariate analysis. CONCLUSIONS: • Under-graded tumours are significantly smaller than tumours concordant for the higher grade, indicating that incomplete tumour sampling plays a significant role in Gleason score assignment error. • Surrogate measures of tumour volume may predict those at greatest risk of Gleason score upgrade.

Upgrade in Gleason score between prostate biopsies and pathology following radical prostatectomy significantly impacts upon the risk of biochemical recurrence.

OBJECTIVE: •To determine the effect of an upgrade in Gleason score between initial prostate biopsy and final prostatectomy specimen on the risk of postoperative biochemical recurrence. PATIENTS AND METHODS: •A total of 1629 patients with paired biopsy and radical prostatectomy histology were identified from two prospectively recorded prostate cancer databases. •Information on key clinical and pathological characteristics as well as prostate-specific antigen follow-up was recorded. •Patients who experienced an upgrade in their Gleason score were compared with corresponding patients with concordant tumours of the lower and higher grade. •Kaplan-Meier curves and multivariate models were generated to examine the impact of Gleason score upgrade on the risk of postoperative biochemical recurrence. RESULTS: •Overall, 466 patients (28.6%) experienced an upgrade in their Gleason score post radical prostatectomy, in 88.4% of cases involving a change in a single Gleason score point. •Patients upgraded from Gleason 6 (3 + 3) to Gleason 7 (3 + 4) had pathological characteristics that were very similar to Gleason 7 (3 + 4) concordant tumours, with an identical risk of biochemical recurrence. In contrast, patients upgraded from Gleason score 6 (3 + 3) to Gleason 7 (4 + 3) had tumours with pathological characteristics intermediate between the two concordant groups, which was mirrored by their risk of biochemical recurrence. •Patients with Gleason 7 tumours who experienced a change in the predominant pattern from 3 + 4 to 4 + 3 had tumours that resembled Gleason 7 (4 + 3) concordant tumours, with a similar risk of biochemical recurrence. In contrast, patients upgraded from Gleason 7 to Gleason >7 had tumours with intermediate pathological characteristics, and a risk of biochemical recurrence that was significantly different to concordant tumours of the lower and higher grade. •In multivariate models, a change in Gleason score was an independent predictor of biochemical recurrence in the preoperative setting only. •Although a difference in Gleason score was an independent predictor of recurrence in concordant tumours in models based on postoperative variables, an upgrade in Gleason score in discordant tumours was not, with differences in co-segregated adverse pathological characteristics being more predictive. CONCLUSIONS: •Patients experiencing an upgrade in their Gleason score between biopsy and final specimen exhibit significantly more aggressive pathological features than corresponding concordant tumours, and a higher risk of biochemical recurrence post radical prostatectomy. •As Gleason score can be more accurately assessed preoperatively than other prognostic tumour features, continued effort is required to identify those most at risk of upgrading, and to refine biopsy strategies to reduce sampling error.

Prostate tumour volume is an independent predictor of early biochemical recurrence in a high risk radical prostatectomy subgroup.

AIMS: To assess if accurately determined tumour volume variables could serve as independent predictors of early biochemical recurrence in high risk prostate cancer patients who underwent radical prostatectomy. METHODS: Tumour volume variables were calculated by digital planimetry in 269 prostatectomy specimens of patients with high risk prostate cancer. The associations to biochemical progression of tumour volume and clinicopathological variables, including age, pre-operative prostate specific antigen (PSA) levels, final Gleason score, pathological T stage, and surgical margins, were examined using univariate and multivariate Cox proportional hazards analyses. RESULTS: Median tumour volume was 3.7 ml [interquartile range (IQR) 2.1-6.1 mL] and median follow-up time was 12 months (IQR 6-24 months). Biochemical recurrence occurred in 64 men (24%) during this period, with a median time to recurrence of 7.5 months (IQR 3.0-15.5 months). On univariate analysis all of the tumour volume variables were strongly correlated with the clinicopathological variables, as well as biochemical recurrence (p < 0.001). On multivariate analysis, we found that tumour volume variables served as independent predictors of PSA progression whilst other routinely reported pathological variables did not. CONCLUSION: Accurately assessing tumour volume in the high risk setting may aid in identifying patients at greatest risk of developing early biochemical recurrence and most in need of adjuvant therapy.