Prostate biopsy strategies

Integration of PSAd and multiparametric MRI to forecast biopsy outcomes in biopsy-naïve patients with PSA 4~20 ng/ml

Introduction

This study aims to investigate whether the transrectal ultrasound-guided combined biopsy (CB) improves the detection rates of prostate cancer (PCa) and clinically significant PCa (csPCa) in biopsy-naïve patients. We also aimed to compare the Prostate Imaging Reporting and Data System (PI-RADS v2.1) score, ADC values, and PSA density (PSAd) in predicting csPCa by the combined prostate biopsy.

Methods

This retrospective and single-center study included 389 biopsy-naïve patients with PSA level 4~20 ng/ml, of whom 197 underwent prebiopsy mpMRI of the prostate. The mpMRI-based scores (PI-RADS v2.1 scores and ADC values) and clinical parameters were collected and evaluated by logistic regression analyses. Multivariable models based on the mpMRI-based scores and clinical parameters were developed by the logistic regression analyses to forecast biopsy outcomes of CB in biopsy-naïve patients. The ROC curves measured by the AUC values, calibration plots, and DCA were performed to assess multivariable models.

Results

The CB can detect more csPCa compared with TRUSB (32.0% vs. 53%). The Spearman correlation revealed that Gleason scores of the prostate biopsy significantly correlated with PI-RADS scores and ADC values. The multivariate logistic regression confirmed that PI-RADS scores 4, 5, and prostate volume were important predictors of csPCa. The PI-RADS+ADC+PSAd (PAP) model had the highest AUCs of 0.913 for predicting csPCa in biopsy-naïve patients with PSA level 4~20 ng/ml. When the biopsy risk threshold of the PAP model was greater than or equal to 0.10, 51% of patients could avoid an unnecessary biopsy, and only 5% of patients with csPCa were missed.

Conclusion

The prebiopsy mpMRI and the combined prostate biopsy have a high CDR of csPCa in biopsy-naïve patients. A multivariable model based on the mpMRI-based scores and PSAd could provide a reference for clinicians in forecasting biopsy outcomes in biopsy-naïve patients with PSA 4~20 ng/ml and make a more comprehensive assessment during the decision-making of the prostate biopsy.

Clinical outcome and safety of holmium laser prostate enucleation after transrectal prostate biopsies for benign prostatic hyperplasia

PURPOSE

This study aimed to assess the clinical outcome and safety of holmium laser enucleation of the prostate (HoLEP) following transrectal ultrasound-guided prostate biopsy (TR biopsy) in the treatment of benign prostate hyperplasia.

MATERIALS AND METHODS

We retrospectively analyzed data from 556 patients who underwent HoLEP between 2014 and 2021. The patients were categorized into six groups: Group 1-A (n=45) underwent HoLEP within four months post TR biopsy. Group 1-B (n=94) underwent HoLEP more than four months post TR biopsy. Group 1-C (n=120) underwent HoLEP after a single TR biopsy. Group 1-D (n=19) underwent HoLEP after two or more TR biopsies. Group 1-total (n=139, group 1-A+group 1-B or group 1-C+group 1-D) underwent HoLEP post TR biopsy. Group 2 (control group, n=417) underwent HoLEP without prior TR biopsy. We examined perioperative parameters, safety, and functional outcomes.

RESULTS

The age, body mass index, International Prostate Symptom Score (IPSS), uroflowmetry, and comorbid diseases between group 1-total and group 2 were comparable. However, group 1-total exhibited significantly elevated prostate-specific antigen levels and larger prostate volumes (p<0.01). Perioperative factors like enucleation time, enucleation weight, and catheterization duration were notably higher in group 1-total (p<0.01). All groups showed significant improvements in IPSS, postvoid residual urine, and maximum flow rate during the 1-year postoperative period (p<0.05). The rates of postoperative complications were similar between group 1-total and group 2.

CONCLUSIONS

Enucleation time and catheterization duration were significantly longer in the TR biopsy group. However, postoperative complications were not significantly different between TR biopsy and non-TR biopsy groups.

Effect of training and individual operator's expertise on prostate cancer detection through prostate biopsy: Implications for the current quantitative training evaluation system

Purpose

This study was conducted to evaluate the relevance of training and experience to gaining expertise in prostate biopsy based on an assessment of outcomes from the performance of urology residents.

Materials and Methods

We retrospectively reviewed the medical records of 10,299 patients who underwent prostate biopsy by 50 operators under a unified urology residency program. The number of prostate biopsies performed by an operator for each patient was used as an indicator of operator experience. Residents were grouped into quartiles according to cancer detection rates in the first 50 and the last 50 procedures.

Results

Among 10,299 patients (median age, 67.5 years; median prostate-specific antigen [PSA], 7.04 ng/mL), the overall prostate cancer detection rate and that for patients with PSA <10.0 ng/mL were 37.0% and 25.9%, respectively. Operator experience was a significant predictor for cancer detection in patients with PSA <10.0 ng/mL. Cancer detection rates and the proportion of more advanced prostate cancers were higher in the last 50 cases than in the first 50 cases. Detection rates varied significantly among operator; residents with higher detection rates at training initiation showed even higher detection rates after additional training.

Conclusions

Training that adds to the cumulative experience of a trainee appears to play a meaningful role in improving cancer detection rates. The level of skill required to achieve mastery for independent practice may be assessed from the accuracy results of prostate biopsy procedures, and trainees with poor rates will require more technical training to improve precision.

Anterior and apical samplings during transperineal image-guided prostate biopsy

INTRODUCTION

Concurrent systematic biopsies during image-guided targeted biopsies of the prostate were found to improve the detection rate of clinically significant prostate cancer (CSPC). However, these biopsies do not routinely include anterior or apical sampling. We aimed to evaluate the significance of anterior and apical samplings during combined biopsies.

METHODS

After obtaining institutional review board approval we identified 303 consecutive patients who underwent transperineal combined biopsies of the prostate between 2017-2020. Systematic biopsies were obtained from the peripheral zone, anterior zone, and apex. Study outcomes included CSPC and any cancer on anterior or apical biopsies. Logistic regression analyses were used to evaluate the association between pre-biopsy characteristics and study outcomes.

RESULTS

Median prostatic-specific-antigen value was 6.8 ng/dL. Most patients had stage T1c disease (77%). Overall, combined biopsies detected CSPC in 87 patients (29%). Any cancer and CSPC in the anterior zone were found in 54 (18%) and 19 (6%) patients, respectively. Any cancer and CSPC in the apex were found in 54 (18%) and 16 (5%) patients, respectively. Anterior/apical samplings upgraded the pathological result in 19 patients (6%). Logistic regression analyses demonstrated that PI-RADS 5 lesions predicted the presence of CSPC in both the anterior zone (OR = 8, 95%CI = 3-22, P <0.001) and apex (OR = 4, 95%CI = 1-10, P = 0.01).

CONCLUSIONS

Avoiding anterior and apical samplings during prostate biopsy does not result in substantial under-diagnosis of significant cancer. However, these areas are easily accessible using the transperineal approach and should be sampled in selected patients, particularly those with PI-RADS 5 lesions.

Initial outcomes of local anaesthetic freehand transperineal prostate biopsies in the outpatient setting

OBJECTIVES

To evaluate the histopathological outcomes, morbidity and tolerability of freehand transperineal (TP) prostate biopsies using the PrecisionPoint™ access system (Perineologic, Cumberland, MD, USA) under local anaesthetic (LA) in the day surgery and outpatient environments, as systematic and targeted biopsies can be taken with the potential for reduced morbidity, particularly sepsis.

PATIENTS AND METHODS

In all, 176 patients underwent freehand TP prostate biopsies from May 2016 to November 2017. The procedure was carried out either under LA alone or with the addition of sedation. Magnetic resonance imaging (MRI) scans were reported using the Prostate Imaging-Reporting and Data System (PI-RADS), version 2. Tolerability was assessed using a visual analogue scale pain score for each procedural stage. Histopathological outcomes and complications were recorded.

RESULTS

The mean (range) age was 65 (36-83) years, median (range) prostate-specific antigen level was 7.9 (0.7-1374) ng/mL, and the mean (range) prostate volume 45 (15-157) mL. Biopsies were taken under LA alone (160 patients, 90%) or under LA with sedation (16, 9%). The main indication for biopsy was primary diagnosis (88.6%). In all, 91 (52%) patients underwent systematic TP biopsies (mean 24.2 cores). Cognitive MRI-targeted biopsies alone were performed in 45 patients (26%; mean 6.8 cores), and 40 (23%) had both systematic and target biopsies (mean 27.9 cores). Of the 75 patients who had primary systematic biopsies alone, 46 (61%) were positive, and 28/46 (60.9%) were diagnosed with clinically significant disease (Gleason ≥3+4). VAS pain scores were greatest during LA administration. There were five complications (2.8%, Clavien-Dindo Grade I/II). No patients developed urosepsis.

CONCLUSIONS

Freehand TP biopsies using the PrecisionPoint access system is a safe, tolerable and effective method for systematic and targeted biopsies under LA in the outpatient setting. It has replaced transrectal biopsies in our centre and has potential to transform practice.

The use of prostate MR for targeting prostate biopsies

Management of prostate cancer relies heavily on accurate risk stratification obtained through biopsies, which are conventionally performed under transrectal ultrasound (TRUS) guidance. Yet, multiparametric MRI has grown to become an integral part of the care of males with known or suspected prostate cancer. This article will discuss in detail the different MRI-targeted biopsy techniques, their advantages and disadvantages, and the impact they have on patient management.

Detection of aggressive prostate cancer associated glycoproteins in urine using glycoproteomics and mass spectrometry

Clinical management of prostate cancer remains a significant challenge due to the lack of available tests for guiding treatment decisions. The blood prostate-specific antigen test has facilitated early detection and intervention of prostate cancer. However, blood prostate-specific antigen levels are less effective in distinguishing aggressive from indolent prostate cancers and other benign prostatic diseases. Thus, the development of novel approaches specific for prostate cancer that can differentiate aggressive from indolent disease remains an urgent medical need. In the current study, we evaluated urine specimens from prostate cancer patients using LC-MS/MS, with the aim of identifying effective urinary prostate cancer biomarkers. Glycoproteins from urine samples of prostate cancer patients with different Gleason scores were characterized via solid phase extraction of N-linked glycosite-containing peptides and LC-MS/MS. A total of 2923 unique glycosite-containing peptides were identified. Glycoproteomic comparison on urine and tissues from aggressive and non-aggressive prostate cancers as well as sera from prostate cancer patients revealed that the majority of AG prostate cancer associated glycoproteins were more readily detected in patient's urine than serum samples. Our data collectively indicate that urine provides a potential source for biomarker testing in patients with AG prostate cancer.

Association and regulation of protein factors of field effect in prostate tissues

Field effect or field cancerization denotes the presence of molecular aberrations in structurally intact cells residing in histologically normal tissues adjacent to solid tumors. Currently, the etiology of prostate field‑effect formation is unknown and there is a prominent lack of knowledge of the underlying cellular and molecular pathways. We have previously identified an upregulated expression of several protein factors representative of prostate field effect, i.e., early growth response-1 (EGR‑1), platelet-derived growth factor‑A (PDGF‑A), macrophage inhibitory cytokine‑1 (MIC‑1), and fatty acid synthase (FASN) in tissues at a distance of 1 cm from the visible margin of intracapsule prostate adenocarcinomas. We have hypothesized that the transcription factor EGR‑1 could be a key regulator of prostate field‑effect formation by controlling the expression of PDGF‑A, MIC‑1, and FASN. Taking advantage of our extensive quantitative immunofluorescence data specific for EGR‑1, PDGF‑A, MIC‑1, and FASN generated in disease‑free, tumor‑adjacent, and cancerous human prostate tissues, we chose comprehensive correlation as our major approach to test this hypothesis. Despite the static nature and sample heterogeneity of association studies, we show here that sophisticated data generation, such as by spectral image acquisition, linear unmixing, and digital quantitative imaging, can provide meaningful indications of molecular regulations in a physiologically relevant in situ environment. Our data suggest that EGR‑1 acts as a key regulator of prostate field effect through induction of pro‑proliferative (PDGF‑A and FASN), and suppression of pro‑apoptotic (MIC‑1) factors. These findings were corroborated by computational promoter analyses and cell transfection experiments in non‑cancerous prostate epithelial cells with ectopically induced and suppressed EGR‑1 expression. Among several clinical applications, a detailed knowledge of pathways of field effect may lead to the development of targeted intervention strategies preventing progression from pre-malignancy to cancer.

Targeted prostate biopsy: value of multiparametric magnetic resonance imaging in detection of localized cancer

Prostate cancer is the second most common cancer in men, with 1.1 million new cases worldwide reported by the World Health Organization in one recent year. Transrectal ultrasound (TRUS)-guided biopsy has been used for the diagnosis of prostate cancer for over 2 decades, but the technique is usually blind to cancer location. Moreover, the false negative rate of TRUS biopsy has been reported to be as high as 47%. Multiparametric magnetic resonance imaging (mp-MRI) includes T1- and T2-weighted imaging as well as dynamic contrast-enhanced (DCE) and diffusion-weighted imaging (DWI). mp-MRI is a major advance in the imaging of prostate cancer, enabling targeted biopsy of suspicious lesions. Evolving targeted biopsy techniques-including direct in-bore biopsy, cognitive fusion and software-based MRI-ultrasound (MRI-US) fusion-have led to a several-fold improvement in cancer detection compared to the earlier method. Importantly, the detection of clinically significant cancers has been greatly facilitated by targeting, compared to systematic biopsy alone. Targeted biopsy via MRI-US fusion may dramatically alter the way prostate cancer is diagnosed and managed.

Inflammation and prostate cancer: friends or foe?

INTRODUCTION

Prostate cancer is the most common non-cutaneous malignancy diagnosed in men. Moving from histological observations since a long time, it has been recognized that innate and adaptive immunity actively participates in the pathogenesis, surveillance, and progression of prostate cancer.

MATERIALS AND METHODS

A PubMed and Web of Science databases search was performed for studies providing evidence on the roles of the innate and adaptive immunity during the development and progression of prostate cancer.

CONCLUSIONS

There are growing evidences that chronic inflammation is involved in the regulation of cellular events in prostate carcinogenesis, including disruption of the immune response and regulation of the tumor microenvironment. This review discusses the role played by the innate and adaptive immune system in the local progression of prostate cancer, and the prognostic information that we can currently understand and exploit.

What is the ideal core number for ultrasound-guided prostate biopsy?

Purpose

We evaluated the utility of 10-, 12-, and 16-core prostate biopsies for detecting prostate cancer (PCa) and correlated the results with prostate-specific antigen (PSA) levels, prostate volumes, Gleason scores, and detection rates of high-grade prostatic intraepithelial neoplasia (HGPIN) and atypical small acinar proliferation (ASAP).

Materials and Methods

A prospective controlled study was conducted in 354 consecutive patients with various indications for prostate biopsy. Sixteen-core biopsy specimens were obtained from 351 patients. The first 10-core biopsy specimens were obtained bilaterally from the base, middle third, apex, medial, and latero-lateral regions. Afterward, six additional punctures were performed bilaterally in the areas more lateral to the base, middle third, and apex regions, yielding a total of 16-core biopsy specimens. The detection rate of carcinoma in the initial 10-core specimens was compared with that in the 12- and 16-core specimens.

Results

No significant differences in the cancer detection rate were found between the three biopsy protocols. PCa was found in 102 patients (29.06%) using the 10-core protocol, in 99 patients (28.21%) using the 12-core protocol, and in 107 patients (30.48%) using the 16-core protocol (p=0.798). The 10-, 12-, and 16-core protocols were compared with stratified PSA levels, stratified prostate volumes, Gleason scores, and detection rates of HGPIN and ASAP; no significant differences were found.

Conclusions

Cancer positivity with the 10-core protocol was not significantly different from that with the 12- and 16-core protocols, which indicates that the 10-core protocol is acceptable for performing a first biopsy.

Analysis of prostate cancer localization toward improved diagnostic accuracy of transperineal prostate biopsy

PURPOSE

Delineating the precise localization of prostate cancer is important in improving the diagnostic accuracy of prostate biopsy.

METHODS

In Juntendo University Nerima Hospital, initial 12-core or repeat 16-core biopsies were performed using a transrectal ultrasound guided transperineal prostate biopsy method. We step-sectioned prostates from radical prostatectomy specimens at 5-mm intervals from the urethra to the urinary bladder and designated five regions: the (1) Apex, (2) Apex-Mid, (3) Mid, (4) Mid-Base, and (5) Base. We then mapped prostate cancer localization on eight zones around the urethra for each of those regions.

RESULTS

Prostate cancer was detected in 93 cases of 121 cases (76.9%) in the Apex, in 115 cases (95.0%) in the Apex-Mid, in 101 cases (83.5%) in the Mid, in 71 cases (58.7%) in the Mid-Base, and in 23 cases (19.0%) in the Base. In 99.2% of all cases, prostate cancers were detected from the Apex to Mid regions. For this reason, transperineal prostate biopsies have routinely been prioritized in the Apex, Apex-Mid, and Mid regions, while the Base region of the prostate was considered to be of lesser importance. Our analyses of prostate cancer localization revealed a higher rate of cancer in the posterior portion of the Apex, antero-medial and postero-medial portion of the Apex-Mid and antero-medial and postero-lateral portion of the Mid. The transperineal prostate biopsies in our institute performed had a sensitivity of 70.9%, a specificity of 96.6%, a positive predictive value (PPV) of 92.2% and a negative predictive value (NPV) of 85.5%.

CONCLUSIONS

The concordance of prostate cancer between prostatectomy specimens and biopsies is comparatively favorable. According to our study, the diagnostic accuracy of transperineal prostate biopsy can be improved in our institute by including the anterior portion of the Apex-Mid and Mid regions in the 12-core biopsy or 16-core biopsy, such that a 4-core biopsy of the anterior portion is included.

Can microfocal prostate cancer be regarded as low-risk prostate cancer?

PURPOSE

Prostate specific antigen (PSA) screening for prostate cancer has become widespread, the prostate biopsy technique has evolved, and the occurrence of low-risk prostate cancer has been increasing. Even low-risk patients may demonstrate disease upgrading or upstaging. We aimed to evaluate the clinical importance of a single microfocal prostate cancer at biopsy in patients subsequently treated with radical prostatectomy.

METHODS

A total of 337 cases of patients who underwent radical prostatectomy after prostate biopsies were retrospectively reviewed. Microfocal prostate cancer was defined as Gleason score 6 and a single positive core with ≤5% cancer involvement after the standard 12-core extended biopsy.

RESULTS

Of the 337 prostatectomy specimens, 22 (6.5%) were microfocal prostate cancer based on prostate biopsy. On final pathology, microfocal patients were found to have significant 45% Gleason score upgrading (P=0.02) and 27% positive surgical margins (P=0.04) despite low PSA, compared with the nonmicrofocal prostate cancer group. Gleason upgrading was significantly higher in the microfocal prostate cancer group (P=0.02), whereas Gleason downgrading was significantly higher in the nonmicrofocal prostate cancer group (P<0.01). Furthermore, biochemical recurrence rate was no different between microfocal and nonmicrofocal prostate cancer at mean 31 months (P=0.18). Overall, 13 of 22 cases (53.1%) in the microfocal prostate cancer group showed Gleason upgrading or stage upgrading.

CONCLUSIONS

Based on higher rates of Gleason score upgrading or stage upgrading cases in microfocal prostate cancer group, compared with nonmicrofocal prostate cancer group, active surveillance should be cautiously applied to these patients.

Localization of higher grade tumor foci in potential candidates for active surveillance who opt for radical prostatectomy

PURPOSE

To investigate actual intraprostatic location of higher graded tumor foci undetected via standard transrectal ultrasound-guided prostate biopsy amongst patients who would be clinically considered appropriate candidates for active surveillance (AS) but underwent radical prostatectomy (RP).

METHODS

We reviewed entirely-submitted and whole-mounted RP specimens from 169 men who were deemed appropriate for AS clinically, but opted for RP and were found to have higher grade tumors. For each case, tumor nodules were circled and color-coded in a grade-specific manner and digitally scanned to created tumor maps. The locations of tumor foci with Gleason grade ≥4 were stratified by specific sites: anterior, anterolateral, lateral only (not clearly anterior or posterior), posterior, and posterolateral area.

RESULTS

Of 169 patients, 86% had clinical stage T1c and 14% T2a. RP Gleason score 7 in all but two men. Higher-grade tumor foci were localized to: anterior (n=66, 39%), anterolateral (n=4, 2%), lateral only (not clearly anterior or posterior) (n=5, 3%), posterior (n=52, 31%), and posterolateral (n=42, 25%) prostate, respectively.

CONCLUSIONS

Among patients deemed clinically appropriate for AS, higher-grade tumor foci missed by standard prostate biopsies were localized to both the anterior and posterior prostate, without predominance of a particular area. These findings lend additional support to performing repeat standard prostate biopsy in potential candidates for AS and should be considered in efforts to optimize current biopsy strategies for the selection of AS patients.

Anti-tumor effects of the peptide TMTP1-GG-D(KLAKLAK)(2) on highly metastatic cancers

The treatment of cancer such as oligonucleotides or peptides requires efficient delivery systems. A novel peptide, TMTP1, previously derived and identified in our laboratory showed remarkable ability to target highly metastatic tumors both in vitro and in vivo, even at the early stage of occult metastasis foci. TMTP1 moderately inhibited tumor cell viability, although not enough to deem it an efficient killer of tumor cells. In this study, we sought to enhance the anti-tumor activity of TMTP1. To do this, we fused it to an antimicrobial peptide, (D)(KLAKLAK)(2), and termed the resulting peptide TMTP1-DKK. We found that TMTP1-DKK could trigger rapid apoptosis in human prostate and gastric cancer cells through both the mitochondrial-induced apoptosis pathway and the death receptor pathway. Furthermore, direct injection of TMTP1-DKK into mice with prostate and gastric xenograft cancers resulted in reduction of tumor volumes and a significant delay in tumor progression and metastasis in vivo. These results suggest that TMTP1-DKK may serve as a powerful therapeutic agent for metastatic tumors.

Markers of field cancerization: proposed clinical applications in prostate biopsies

Field cancerization denotes the occurrence of genetic, epigenetic, and biochemical aberrations in structurally intact cells in histologically normal tissues adjacent to cancerous lesions. This paper tabulates markers of prostate field cancerization known to date and discusses their potential clinical value in the analysis of prostate biopsies, including diagnosis, monitoring progression during active surveillance, and assessing efficacy of presurgical neoadjuvant and focal therapeutic interventions.

New variants at 10q26 and 15q21 are associated with aggressive prostate cancer in a genome-wide association study from a prostate biopsy screening cohort

PURPOSE

To identify and examine polymorphisms of genes associated with aggressive and clinical significant forms of prostate cancer among a screening cohort.

EXPERIMENTAL DESIGN

We conducted a genome-wide association study among patients with aggressive forms of prostate cancer and biopsy-proven normal controls ascertained from a prostate cancer screening program. We then examined significant associations of specific polymorphisms among a prostate cancer screened cohort to examine their predictive ability in detecting prostate cancer.

RESULTS

We found significant associations between aggressive prostate cancer and five single nucleotide polymorphisms (SNPs) in the 10q26 (rs10788165, rs10749408, and rs10788165, p value for association 1.3 × 10(-10 ) to 3.2 × 10(-11) ) and 15q21 (rs4775302 and rs1994198, p values for association 3.1 × 10(-8 ) to 8.2 × 10(-9)) regions. Results of a replication study done in 3439 patients undergoing a prostate biopsy, revealed certain combinations of these SNPs to be significantly associated not only with prostate cancer but with aggressive forms of prostate cancer using an established classification criterion for prostate cancer progression (odds ratios for intermediate to high-risk disease 1.8-3.0, p value 0.003-0.001). These SNP combinations were also important clinical predictors for prostate cancer detection based on nomogram analysis that assesses prostate cancer risk.

CONCLUSIONS

Five SNPs were found to be associated with aggressive forms of prostate cancer. We demonstrated potential clinical applications of these associations.

Detection and verification of glycosylation patterns of glycoproteins from clinical specimens using lectin microarrays and lectin-based immunosorbent assays

Aberrant glycosylation is a fundamental characteristic of progression of diseases such as cancer. Therefore, characterization of glycosylation patterns of proteins from disease tissues may identify changes specific to the disease development and improve diagnostic performance. Thus, analysis strategies with sufficient sensitivity for evaluation of glycosylation patterns in clinical specimens are needed. Here, we describe an analytical strategy for detection and verification of glycosylation patterns. It is based on a two-phase platform including a pattern discovery phase to identify the glycosylation changes using high-density lectin microarrays and a verification phase by developing lectin-based immunosorbent assays using the identified lectins. We evaluated the analytical performance of the platform using the glycoprotein standard and found that the lectin microarray could detect specific bindings of glycoprotein to lectins at the nanogram level and the lectin-based immunosorbent assay could be used for verification of protein glycosylation. We then applied the approach to the analysis of glycosylation patterns of two glycoproteins, which are highly expressed in prostate cancer in our prior studies, prostate specific antigen (PSA) and membrane metallo-endopeptidase (MME), from aggressive (AC) and nonaggressive prostate cancer (NAC) tissues. The observed differences in glycosylation patterns of PSA and MME may represent a significant clinical importance and could be used to develop multiplex assays for diagnosis of aggressive prostate cancer.

Quantitative glycoproteomic analysis of optimal cutting temperature-embedded frozen tissues identifying glycoproteins associated with aggressive prostate cancer

Prostate cancer is the most common malignancy in men in the United States, and one in seven men with prostate cancer dies of the disease. A major issue of prostate diagnosis is that there is no good method to reliably distinguish aggressive prostate cancer from nonaggressive prostate cancer. This leads to significant unnecessary suffering among prostate cancer patients and massive unnecessary health care expenditures. In this study, we aim to identify glycoproteins associated with aggressive prostate cancer using optimal cutting temperature (OCT)-embedded frozen tissues obtained from patients with known clinical outcome. To eliminate the interference of mass spectrometric analysis by the compounds in OCT and identify extracellular proteins that are likely to serve as biomarkers in body fluids, we employed glycoproteomic analysis using solid-phase extraction of glycopeptides, which allowed the immobilization of glycopeptides to solid support and removal of OCT from sample proteins before releasing the glycopeptides from the solid support for mass spectrometry analysis. Tumor tissues were cryostat microdissected from four cases of aggressive and four cases of nonaggressive prostate tumors, and glycopeptides were isolated and labeled with iTRAQ reagents before the samples were analyzed with LTQ Orbitrap Velos. From the aggressive prostate cancer tissues, we identified the overexpression of three glycoproteins involved in an extracellular matrix remodeling and further examined two glycoproteins, cathepsin L and periostin, using Western blot and immunohistochemistry analyses. This is the first proteomic study to identify proteins potentially associated with aggressive prostate cancer using OCT-embedded frozen tissues. Further study of these proteins will be needed to understand the roles of extracellular matrix proteins in cancer progression and their potential clinical utility in improving diagnosis of aggressive prostate cancer.

Prostate cancer detection after a negative prostate biopsy: lessons learnt in the Cleveland Clinic experience

Urologists are often faced with the dilemma of managing patients with a negative initial prostate biopsy in whom clinical or pathological risk for prostate cancer still exists. Such real-life challenging scenarios might raise questions such as: Who should undergo further biopsies? What are the optimal predictors for prostate cancer on subsequent biopsies? What is the optimal biopsy protocol that should be used? When to stop the biopsy cascade? The last decade has witnessed numerous studies that have analyzed factors conferring a significant risk for cancer discovered on repeat biopsies. We and others have developed predictive models to aid decision-making regarding pursuing further biopsies. For decades, high-grade prostatic intraepithelial neoplasia has been considered a strong risk indicator for subsequent cancer. However, it has been recently shown that only through segmentation of this heterogeneous population does the real risk profile emerge. Biopsy templates underwent modification regarding the number and location of cores with emergence of the transrectal or brachytherapy grid transperineal saturation biopsy. However, the best biopsy protocol remains controversial. We have refined the initial biopsy template to a 14 core initial biopsy template that optimizes cancer detection, and have shown that transrectal saturation biopsy significantly improves cancer detection for repeat biopsy. Another concern is the overdiagnosis of clinically insignificant cancer on repeat biopsies, so we explored ways to limit this, and to deal with its ramifications. Through carrying out a Medline literature search, we critically evaluated pertinent articles together with emphasis of our own journey in this arena to assist in the decision-making process for repeat biopsy population.

Percentage of free prostate-specific antigen: implications in modern extended scheme prostate biopsy

OBJECTIVES

To validate the performance of percentage of free prostate-specific antigen (%fPSA) in men undergoing extended scheme biopsy. The current cutoff values for %fPSA were chosen using data from sextant biopsies, which have been known to miss a significant number of prostate cancer cases. Additionally, we sought to validate the use of %fPSA in men with a total PSA < 4.0 ng/mL or > 10.0 ng/mL.

METHODS

We evaluated %fPSA performance in 1077 men who had undergone initial extended prostate biopsy. The men were categorized according to their PSA level into 2 groups (>4.0 and ≤4.0) ng/mL.

RESULTS

The overall cancer detection rate was 42.1%. The mean PSA level was 7.6 ng/mL, and the mean %fPSA was 18.0%. The area under the curve for %fPSA was 0.59 (95% confidence interval 0.57-0.61) for all PSA levels, comparable to previous reports from sextant biopsy series. The performance of %fPSA in predicting prostate cancer on initial extended biopsy was improved with a PSA level of ≤4.0 ng/mL (area under the curve 0.66, 95% confidence interval 0.62-0.70) compared with a PSA level >4.0 ng/mL (area under the curve 0.57, 95% confidence interval 0.55-0.59; P < .001). A specificity of 85% was achieved for a %fPSA cutoff of 11% for the ≤4.0-ng/mL group and 10% for the >4.0-ng/mL group.

CONCLUSIONS

The performance of %fPSA in predicting the presence of prostate cancer was not altered when an extended biopsy scheme was used. Although a %fPSA level greater than our cutoffs would not rule out prostate cancer, a low %fPSA would be particularly useful in predicting prostate cancer, especially in men with normal digital rectal examination findings and a PSA level <4 ng/mL.

Prostate biopsy in Western Australia 1998-2004

We reviewed the status of prostate cancer diagnosis in Western Australia (WA) with the aim of improving decision-making about PSA testing and prostate biopsy. Our patient cohort was 5145 men undergoing an initial biopsy for prostate cancer diagnosis in WA between 1998 and 2004. Transrectal ultrasound-guided biopsies were performed by one of 18 clinicians whereas all pathology was assessed by one urological pathologist. Cancer detection rates were 59% for initial biopsies and 32% for repeat biopsies. High-grade cancer (Gleason sum > or =7) accounted for 69 and 38% of tumours diagnosed on initial and repeat biopsy, respectively. The rates of cancer diagnosis and detection of high-grade tumours were both 1.6-fold higher in WA patients compared with those obtained at baseline screening of the Prostate, Lung, Colorectal and Ovarian (PLCO) cancer screening trial of US men (P<0.001). These higher than expected rates of cancer detection and high histological grade indicate that urological practice in WA between 1998 and 2004 was significantly more conservative than US practice over this time period, probably leading to underdiagnosis of prostate cancer. Our findings may be relevant to other countries where urological practice differs from that in the United States.

Operator is an independent predictor of detecting prostate cancer at transrectal ultrasound guided prostate biopsy

PURPOSE

We investigated whether interoperator differences exist in the setting of prostate cancer detection by transrectal ultrasound guided prostate biopsy. Our secondary aim was to investigate whether a learning curve exists for prostate cancer detection.

MATERIALS AND METHODS

A prospective database from 2000 to 2008 including 9,072 transrectal ultrasound guided prostate biopsies at our institution was limited to 4,724 done at initial presentation. Biopsies were performed by 4 uroradiologists. The OR for detecting cancer on transrectal ultrasound guided prostate biopsy was calculated for likely independent prognostic variables, including operator. We also examined the rate of biopsy positivity in increments, comparing the first and last cohorts. The senior radiologist (AT) with the most biopsies (75%) was considered the referent for prostate cancer detection. Univariate and multivariate logistic regression modeling was used to determine significant covariates with p <0.05 deemed relevant.

RESULTS

Prostate cancer was detected in 2,331 men (49.3%). Operators performed a median of 514 transrectal ultrasound guided prostate biopsies (range 187 to 3,509) with a prostate cancer detection rate of 43.8% to 52.4% (p = 0.001). Other significant covariates were prostate specific antigen, suspicious lesions on ultrasound, nodule on digital rectal examination, smaller prostate volume and increasing patient age. Operator was a significant multivariate predictor of cancer detection (OR 0.67 to 0.89, p = 0.003). No learning curve was detected and biopsy rates were consistent throughout the series.

CONCLUSIONS

Significant differences in prostate cancer detection exist among operators who perform transrectal ultrasound guided prostate biopsy even in the same setting. The volume of previously performed transrectal ultrasound guided prostate biopsies does not appear to influence the positive prostate cancer detection rate, nor could a learning curve be identified. Differences in prostate cancer detection among operators are likely related to unknown differences in expertise or technique. Further research is needed.

[Saturation biopsy in prostate cancer diagnosis]

AIMS

To analyze the results obtained after doing saturation prostate biopsy to a series of patients with high level of PSA. SUBJECTS, MATERIAL AND METHOD: Among 2006 and 2007 saturation biopsies have been realized in our Service to 32 patients with high PSA, previous biopsies without diagnosis of prostate cancer and high suspicion of malignant disease.

RESULTS

The mean age was 65.81 years, with an average of previous biopsies of 2.41 (range: 1 to 5). Mean of PSA was 15.45 ng/dl (range: 5.63 to 35.47 ng/ml). The mean number of cores obtained in the saturation biopsies was of 20.78 (range: 16-26). 13 were diagnosed prostate adenocarcinomas (40.63%), of which 10 had previous diagnosis of PIN or atipia. 8 patients underwent radical prostatectomy, 3 cases were treated with radiotherapy, 1 case was treated with hormonetherapy and the remaining one is kept in watchful waiting. Concordance of Gleason grade was in 6 of 8 patients treated surgically.

CONCLUSIONS

Saturation biopsy is an effective method for the diagnosis of prostate cancer after several negative biopsies and a strong clinical suspicion of malignant pathology. Saturation biopsy is not a first choice procedure for the diagnosis of prostate cancer.