INDIVIDUALIZATION OF THE BIOPSY PROTOCOL ACCORDING TO THE PROSTATE GLAND VOLUME FOR PROSTATE CANCER DETECTION

Interpreting Prostate MRI Reports in the Era of Increasing Prostate MRI Utilization: A Urologist's Perspective

Multi-parametric prostate MRI (mpMRI) is crucial for diagnosing, staging, and assessing treatment response in individuals with prostate cancer. Radiologists, through an accurate and standardized interpretation of mpMRI, stratify patients who may benefit from more invasive treatment or exclude patients who may be harmed by overtreatment. The integration of prostate MRI into the diagnostic pathway is anticipated to generate a substantial surge in the demand for high-quality mpMRI, estimated at approximately two million additional prostate MRI scans annually in Europe. In this review we examine the immediate impact on healthcare, particularly focusing on the workload and evolving roles of radiologists and urologists tasked with the interpretation of these reports and consequential decisions regarding prostate biopsies. We investigate important questions that influence how prostate MRI reports are handled. The discussion aims to provide insights into the collaboration needed for effective reporting.

Automated prostate gland segmentation in challenging clinical cases: comparison of three artificial intelligence methods

OBJECTIVE

Automated methods for prostate segmentation on MRI are typically developed under ideal scanning and anatomical conditions. This study evaluates three different prostate segmentation AI algorithms in a challenging population of patients with prior treatments, variable anatomic characteristics, complex clinical history, or atypical MRI acquisition parameters.

MATERIALS AND METHODS

A single institution retrospective database was queried for the following conditions at prostate MRI: prior prostate-specific oncologic treatment, transurethral resection of the prostate (TURP), abdominal perineal resection (APR), hip prosthesis (HP), diversity of prostate volumes (large ≥ 150 cc, small ≤ 25 cc), whole gland tumor burden, magnet strength, noted poor quality, and various scanners (outside/vendors). Final inclusion criteria required availability of axial T2-weighted (T2W) sequence and corresponding prostate organ segmentation from an expert radiologist. Three previously developed algorithms were evaluated: (1) deep learning (DL)-based model, (2) commercially available shape-based model, and (3) federated DL-based model. Dice Similarity Coefficient (DSC) was calculated compared to expert. DSC by model and scan factors were evaluated with Wilcox signed-rank test and linear mixed effects (LMER) model.

RESULTS

683 scans (651 patients) met inclusion criteria (mean prostate volume 60.1 cc [9.05-329 cc]). Overall DSC scores for models 1, 2, and 3 were 0.916 (0.707-0.971), 0.873 (0-0.997), and 0.894 (0.025-0.961), respectively, with DL-based models demonstrating significantly higher performance (p < 0.01). In sub-group analysis by factors, Model 1 outperformed Model 2 (all p < 0.05) and Model 3 (all p < 0.001). Performance of all models was negatively impacted by prostate volume and poor signal quality (p < 0.01). Shape-based factors influenced DL models (p < 0.001) while signal factors influenced all (p < 0.001).

CONCLUSION

Factors affecting anatomical and signal conditions of the prostate gland can adversely impact both DL and non-deep learning-based segmentation models.

Any Correlation Between Prostate Volume and Incidence of Prostate Cancer: A Review of Reported Data for the Last Thirty Years

PURPOSE

Prostate cancer (PCa) is the most common non-skin cancer in men worldwide and more than 80% of men with PCa also have histo-anatomical findings of benign prostate hyperplasia (BPH). It is well documented that BPH develops in the transition zone (TZ), whereas 80-85% of PCa originates in the peripheral zone (PZ) of the prostate. Possible causal links between both disease entities are controversially discussed in the current literature. Some studies have reported that larger prostates have a decreased incidence of PCa compared to smaller prostates. The purpose of this systematic review is to comprehensively summarize studies analyzing any association between prostate gland volume and incidence of PCa.

METHODS

A thorough literature review was performed between 01.01.1990 through 02.28.2020 using PubMed and applying the "PRISMA" guidelines. Inclusion and exclusion criteria were defined.

RESULTS

Our systematic review found 41 articles reporting an inverse (negative) relationship between prostate gland volume and incidence of prostate cancer. Sample sizes ranged from 114 to 6692 patients in these single institutional and multi-institutional studies. Thirty-nine (95%) of the 41 articles showed a statistically significant inverse relationship. In our search, no study was found showing a positive correlation between BPH size and the incidence of PCa.

CONCLUSION

To our knowledge, this is the first systematic review on the important clinical question of interaction between prostate size and the incidence of PCa. The results are demonstrating an inverse relationship, and therefore reveal strong evidence that large prostates may be protective of PCa when compared to smaller prostates.

Use of increasing the number of biopsy cores in proportion to prostate size on prostate cancer diagnosis

Objectives:

This study aimed to determine the value of changing the number of biopsy cores in proportion to the size of the prostate in patients who had initial transperineal prostate biopsies.

Materials and methods:

This study included 470 patients who underwent an initial transperineal prostate biopsy. The number of biopsy cores was changed according to the value of the product of the vertical and horizontal diameters of the largest horizontal section of the prostate on transrectal ultrasonography (TRUS). Biopsies were classified into five groups: 12 cores, 14 cores, 18 cores, 20 cores, and 24 cores. Predictive factors for positive biopsy were studied with logistic regression analyses.

Results:

Variables that were significantly associated with positive biopsy were age, prostate-specific antigen density (PSAD), prostate volume (Pvol), and number of biopsy cores in univariate analysis. Age, PSAD, and Pvol were independent predictors in multivariate analysis. There was no significant difference in the number of biopsy cores, and it was not an independent predictor.

Conclusions:

Changing the number of biopsy cores according to the area of the largest horizontal section of the prostate on TRUS had no significant impact in detecting prostate cancer. However, further research is required to confirm this conclusion.

Level of evidence:

Level 2b.

The Comparison of Imaging and Clinical Methods to Estimate Prostate Volume: A Single-Centre Retrospective Study

BACKGROUND

Prostate volume (PV) is a useful tool in risk stratification, diagnosis, and follow-up of numerous prostatic diseases including prostate cancer and benign prostatic hypertrophy. There is currently no accepted ideal PV measurement method.

OBJECTIVE

This study compares multiple means of PV estimation, including digital rectal examination (DRE), transrectal ultrasound (TRUS), and magnetic resonance imaging (MRI), and radical prostatectomy specimens to determine the best volume measurement style.

METHODS

A retrospective, observational, single-site study with patients identified using an institutional database was performed. A total of 197 patients who underwent robot-assisted radical prostatectomy were considered. Data collected included age, serum PSA at the time of the prostate biopsy, clinical T stage, Gleason score, and PVs for each of the following methods: DRE, TRUS, MRI, and surgical specimen weight (SPW) and volume.

RESULTS

A paired t test was performed, which reported a statistically significant difference between PV measures (DRE, TRUS, MRI ellipsoid, MRI bullet, SP ellipsoid, and SP bullet) and the actual prostate weight. Lowest differences were reported for SP ellipsoid volume (M = -2.37; standard deviation [SD] = 10.227; t[167] = -3.011; and p = 0.003), MRI ellipsoid volume (M = -4.318; SD = 9.53; t[167] = -5.87; and p = 0.000), and MRI bullet volume (M = 5.31; SD = 10.77; t[167] = 6.387; and p = 0.000).

CONCLUSION

The PV obtained by MRI has proven to correlate with the PV obtained via auto-segmentation software as well as actual SPW, while also being more cost-effective and time-efficient. Therefore, demonstrating that MRI estimated the PV is an adequate method for use in clinical practice for therapeutic planning and patient follow-up.

Determination of Prostate Volume: A Comparison of Contemporary Methods

RATIONALE AND OBJECTIVES

Prostate volume (PV) determination provides important clinical information. We compared PVs determined by digital rectal examination (DRE), transrectal ultrasound (TRUS), magnetic resonance imaging (MRI) with or without three-dimensional (3D) segmentation software, and surgical prostatectomy weight (SPW) and volume (SPV).

MATERIALS AND METHODS

This retrospective review from 2010 to 2016 included patients who underwent radical prostatectomy ≤1 year after multiparametric prostate MRI. PVs from DRE and TRUS were obtained from urology clinic notes. MRI-based PVs were calculated using bullet and ellipsoid formulas, automated 3D segmentation software (MRI-A3D), manual segmentation by a radiologist (MRI-R3D), and a third-year medical student (MRI-S3D). SPW and SPV were derived from pathology reports. Intraclass correlation coefficients compared the relative accuracy of each volume measurement.

RESULTS

Ninety-nine patients were analyzed. Median PVs were DRE 35 mL, TRUS 35 mL, MRI-bullet 49 mL, MRI-ellipsoid 39 mL, MRI-A3D 37 mL, MRI-R3D 36 mL, MRI-S3D 36 mL, SPW 54 mL, SPV-bullet 47 mL, and SPV-ellipsoid 37 mL. SPW and bullet formulas had consistently large PV, and formula-based PV had a wider spread than PV based on segmentation. Compared to MRI-R3D, the intraclass correlation coefficient was 0.91 for MRI-S3D, 0.90 for MRI-ellipsoid, 0.73 for SPV-ellipsoid, 0.72 for MRI-bullet, 0.71 for TRUS, 0.70 for SPW, 0.66 for SPV-bullet, 0.38 for MRI-A3D, and 0.33 for DRE.

CONCLUSIONS

With MRI-R3D measurement as the reference, the most reliable methods for PV estimation were MRI-S3D and MRI-ellipsoid formula. Automated segmentations must be individually assessed for accuracy, as they are not always truly representative of the prostate anatomy. Manual segmentation of the prostate does not require expert training.

Geometric systematic prostate biopsy

OBJECTIVE

The common sextant prostate biopsy schema lacks a three-dimensional (3D) geometric definition. The study objective was to determine the influence of the geometric distribution of the cores on the detection probability of prostate cancer (PCa).

METHODS

The detection probability of significant (>0.5 cm³) and insignificant (<0.2 cm³) tumors was quantified based on a novel 3D capsule model of the biopsy sample. The geometric distribution of the cores was optimized to maximize the probability of detecting significant cancer for various prostate sizes (20-100cm³), number of biopsy cores (6-40 cores) and biopsy core lengths (14-40 mm) for transrectal and transperineal biopsies.

RESULTS

The detection of significant cancer can be improved by geometric optimization. With the current sextant biopsy, up to 20% of tumors may be missed at biopsy in a 20 cm³ prostate due to the schema. Higher number and longer biopsy cores are required to sample with an equal detection probability in larger prostates. Higher number of cores increases both significant and insignificant tumor detection probability, but predominantly increases the detection of insignificant tumors.

CONCLUSION

The study demonstrates mathematically that the geometric biopsy schema plays an important clinical role, and that increasing the number of biopsy cores is not necessarily helpful.

Predictors of prostate cancer in ultrasound-guided transperineal saturation biopsy in Turkish men with multiple prior negative biopsies

BACKGROUND

Transperineal prostate biopsy (STPB) is associated with an improved cancer detection rate and an increase in anterior and apical prostate cancers compared to standard transrectal biopsy.

PATIENTS AND METHODS

A total of 48 men with at least two sets of prior prostate biopsies underwent transrectal ultrasound-guided STPB. Prostate rebiopsy indications were serum prostate-specific antigen (PSA) levels greater than 2.5 ng/mL and/or abnormal digital rectal examination and/or presence of high-grade prostatic intraepithelial neoplasia (HGPIN; ≥2 cores) or atypical small acinar proliferation (ASAP) at previous biopsies. The procedure was performed at dorsal lithotomy position under general anesthesia using a perineal 0.5 cm brachytherapy template attached to the transrectal ultrasound probe. Specimens from each zone were sent separately for pathological examination.

RESULTS

Mean PSA level at STPB was 15.9 ng/mL (range 4.03 to 59.57). An average of 54.5 cores was obtained. Prostate adenocarcinoma was detected in 15 of 48 (31%) patients. Mean percentage of malignant cores was 11.9%. Multivariate logistic regression analysis revealed that age and presence of ASAP or HGPIN at previous biopsies were independent predictors of prostate cancer (p&lt;0.05). No major complications, including sepsis and severe urinary or rectal bleeding, were observed in any of the patients. Five patients (10%) developed acute urinary retention after the procedure requiring urethral catheterization.

CONCLUSIONS

Considerable number of patients with negative multiple biopsies were diagnosed with prostate cancer. STPB is a well-tolerated procedure with minimal morbidity, which can be considered for the diagnosis of prostate cancer in patients with previous negative biopsies.

Optimizing prostate specimen handling for diagnosis and prognosis

Optimal processing, handling, and sampling of prostatic biopsies, transurethral resections, and radical prostatectomy specimens ensure accurate diagnosis and staging. Prognostic factors derived from careful examination of tissue samples are critical for patient management, including cancer volume, extraprostatic extension, surgical margins, vascular/lymphatic invasion, and perineural invasion. This chapter addresses these important issues, including recent recommendations of a consensus panel of the International Society of Urologic Pathologists.

DNA methylation status is more reliable than gene expression at detecting cancer in prostate biopsy

Background:

We analysed critically the potential usefulness of RNA- and DNA-based biomarkers in supporting conventional histological diagnostic tests for prostate carcinoma (PCa) detection.

Methods:

Microarray profiling of gene expression and DNA methylation was performed on 16 benign prostatic hyperplasia (BPH) and 32 cancerous and non-cancerous prostate samples extracted by radical prostatectomy. The predictive value of the selected biomarkers was validated by qPCR-based methods using tissue samples extracted from the 58 prostates and, separately, using 227 prostate core biopsies.

Results:

HOXC6, AMACR and PCA3 expression showed the best discrimination between PCa and BPH. All three genes were previously reported as the most promising mRNA-based markers for distinguishing cancerous lesions from benign prostate lesions; however, none were sufficiently sensitive and specific to meet the criteria for a PCa diagnostic biomarker. By contrast, DNA methylation levels of the APC, TACC2, RARB, DGKZ and HES5 promoter regions achieved high discriminating sensitivity and specificity, with area under the curve (AUCs) reaching 0.95−1.0. Only a small overlap was detected between the DNA methylation levels of PCa-positive and PCa-negative needle biopsies, with AUCs ranging between 0.854 and 0.899.

Conclusions:

DNA methylation-based biomarkers reflect the prostate malignancy and might be useful in supporting clinical decisions for suspected PCa following an initial negative prostate biopsy.

Fully automated prostate segmentation on MRI: comparison with manual segmentation methods and specimen volumes

OBJECTIVE

The objective of our study was to compare calculated prostate volumes derived from tridimensional MR measurements (ellipsoid formula), manual segmentation, and a fully automated segmentation system as validated by actual prostatectomy specimens.

MATERIALS AND METHODS

Ninety-eight consecutive patients (median age, 60.6 years; median prostate-specific antigen [PSA] value, 6.85 ng/mL) underwent triplane T2-weighted MRI on a 3-T magnet with an endorectal coil while undergoing diagnostic workup for prostate cancer. Prostate volume estimates were determined using the formula for ellipsoid volume based on tridimensional measurements, manual segmentation of triplane MRI, and automated segmentation based on normalized gradient fields cross-correlation and graph-search refinement. Estimates of prostate volume based on ellipsoid volume, manual segmentation, and automated segmentation were compared with prostatectomy specimen volumes. Prostate volume estimates were compared using the Pearson correlation coefficient and linear regression analysis. The Dice similarity coefficient was used to quantify spatial agreement between manual segmentation and automated segmentation.

RESULTS

The Pearson correlation coefficient revealed strong positive correlation between prostatectomy specimen volume and prostate volume estimates derived from manual segmentation (R = 0.89-0.91, p < 0.0001) and automated segmentation (R = 0.88-0.91, p < 0.0001). No difference was observed between manual segmentation and automated segmentation. Mean partial and full Dice similarity coefficients of 0.92 and 0.89, respectively, were achieved for axial automated segmentation.

CONCLUSION

Prostate volume estimates obtained with a fully automated 3D segmentation tool based on normalized gradient fields cross-correlation and graph-search refinement can yield highly accurate prostate volume estimates in a clinically relevant time of 10 seconds. This tool will assist in developing a broad range of applications including routine prostate volume estimations, image registration, biopsy guidance, and decision support systems.

Medical technologies for the diagnosis of prostate cancer

Prostate cancer is an extremely prevalent problem, especially in our aging population. The prostate-specific antigen test has revolutionized prostate cancer screening. Significant advances have been made in the usage of prostate-specific antigen and its derivatives, biomarkers, diagnostic imaging techniques, biopsy strategy, biopsy needle design and anesthetic agents. Further improvement in prostate cancer detection hinges on the development of an imaging technique that is tumor specific and sensitive to biological aggressiveness.

How reliable is 12-core prostate biopsy procedure in the detection of prostate cancer?

INTRODUCTION

Prostate biopsies incur the risk of being false-negative and this risk has not yet been evaluated for 12-core prostate biopsy. We calculated the false-negative rate of 12-core prostate biopsy and determined the patient characteristics which might affect detection rate.

METHODS

We included 90 prostate cancer patients (mean age of 64, range: 49-77) diagnosed with transrectal ultrasound guided 12-core prostate biopsy between December 2005 and April 2008. All patients underwent radical retropubic prostatectomy and the 12-core prostate biopsy procedure was repeated on surgical specimen ex-vivo. Results of preoperative and postoperative prostate biopsies were compared. We analyzed the influence of patient age, prostate weight, serum prostate-specific antigen (PSA) level, free/total PSA ratio, PSA density and Gleason score on detection rate.

RESULTS

In 67.8% of patients, prostate cancer was detected with repeated ex-vivo biopsies using the same mapping postoperatively. We found an increase in PSA level, PSA density and biopsy Gleason score; patient age, decreases in prostate weight and free/total PSA ratio yielded higher detection rates. All cores, except the left-lateral cores, showed mild-moderate or moderate internal consistency. Preoperative in-vivo biopsy Gleason scores remained the same, decreased and increased in 43.3%, 8.9% and 47.8% of patients, respectively, on final specimen pathology.

CONCLUSIONS

The detection rate of prostate cancer with 12-core biopsy in patients (all of whom had prostate cancer) was considerably low. Effectively, repeat biopsies can still be negative despite the patient's reality of having prostate cancer. The detection rate is higher if 12-core biopsies are repeated in younger patients, patients with high PSA levels, PSA density and Gleason scores, in addition in patients with smaller prostates, lower free/total PSA ratios.

How reliable is 12-core prostate biopsy procedure in the detection of prostate cancer?

INTRODUCTION

Prostate biopsies incur the risk of being false-negative and this risk has not yet been evaluated for 12-core prostate biopsy. We calculated the false-negative rate of 12-core prostate biopsy and determined the patient characteristics which might affect detection rate.

METHODS

We included 90 prostate cancer patients (mean age of 64, range: 49-77) diagnosed with transrectal ultrasound guided 12-core prostate biopsy between December 2005 and April 2008. All patients underwent radical retropubic prostatectomy and the 12-core prostate biopsy procedure was repeated on surgical specimen ex-vivo. Results of preoperative and postoperative prostate biopsies were compared. We analyzed the influence of patient age, prostate weight, serum prostate-specific antigen (PSA) level, free/total PSA ratio, PSA density and Gleason score on detection rate.

RESULTS

In 67.8% of patients, prostate cancer was detected with repeated ex-vivo biopsies using the same mapping postoperatively. We found an increase in PSA level, PSA density and biopsy Gleason score; patient age, decreases in prostate weight and free/total PSA ratio yielded higher detection rates. All cores, except the left-lateral cores, showed mild-moderate or moderate internal consistency. Preoperative in-vivo biopsy Gleason scores remained the same, decreased and increased in 43.3%, 8.9% and 47.8% of patients, respectively, on final specimen pathology.

CONCLUSIONS

The detection rate of prostate cancer with 12-core biopsy in patients (all of whom had prostate cancer) was considerably low. Effectively, repeat biopsies can still be negative despite the patient's reality of having prostate cancer. The detection rate is higher if 12-core biopsies are repeated in younger patients, patients with high PSA levels, PSA density and Gleason scores, in addition in patients with smaller prostates, lower free/total PSA ratios.

Is sampling transitional zone in patients who had prior negative prostate biopsy necessary?

OBJECTIVE

To assess the necessity of transitional zone sampling of the prostate during repeat prostate biopsy procedures.

METHODS

Patients treated for lower urinary tract symptoms with transurethral resection of the prostate (TURP) from April 2004 to July 2009 whom had at least 1 negative prostate biopsy prior to this treatment were chosen as the study group. A histopathological analysis of surgical specimens was employed to determine cancer detection rates.

RESULTS

A total of 72 patients with the mean age of 66.1, mean prostate-specific antigen (PSA) of 10.4 ng/mL and mean prostate volume of 63.2 cc were included. Of the patients, 50 had 1 biopsy set, 17 had 2 sets, 4 had 3 sets and 1 patient had 4 sets of consecutive biopsies. All biopsy results were negative for prostate cancer. After the analysis of surgical specimens obtained during TURP, cancer was detected in 3 patients (4.2%). Transitional zone sampling during prostate biopsies did not significantly improve the cancer detection rate. Transitional zone sampling was performed in 29 biopsies taken from 20 patients, one of whom (5%) had prostate cancer. The remaining 71 biopsies were taken from 52 patients without transitional zone sampling, and cancer was detected in 2 (3.8%) of them.

CONCLUSIONS

Since no significant difference was observed between patient groups (those with and those without transitional zone biopsies) in the detection of prostate cancer in the transitional zone, strategies for increasing the number of cores taken from transitional zone during repeat biopsies should be reconsidered.

Automated computer-derived prostate volumes from MR imaging data: comparison with radiologist-derived MR imaging and pathologic specimen volumes

PURPOSE

To compare prostate gland volume (PV) estimation of automated computer-generated multifeature active shape models (MFAs) performed with 3-T magnetic resonance (MR) imaging with that of other methods of PV assessment, with pathologic specimens as the reference standard.

MATERIALS AND METHODS

All subjects provided written informed consent for this HIPAA-compliant and institutional review board-approved study. Freshly weighed prostatectomy specimens from 91 patients (mean age, 59 years; range, 42-84 years) served as the reference standard. PVs were manually calculated by two independent readers from MR images by using the standard ellipsoid formula. Planimetry PV was calculated from gland areas generated by two independent investigators by using manually drawn regions of interest. Computer-automated assessment of PV with an MFA was determined by the aggregate computer-calculated prostate area over the range of axial T2-weighted prostate MR images. Linear regression, linear mixed-effects models, concordance correlation coefficients, and Bland-Altman limits of agreement were used to compare volume estimation methods.

RESULTS

MFA-derived PVs had the best correlation with pathologic specimen PVs (slope, 0.888). Planimetry derived volumes produced slopes of 0.864 and 0.804 for two independent readers when compared with specimen PVs. Ellipsoid formula-derived PVs had slopes closest to one when compared with planimetry PVs. Manual MR imaging and MFA PV estimates had high concordance correlation coefficients with pathologic specimens.

CONCLUSION

MFAs with axial T2-weighted MR imaging provided an automated and efficient tool with which to assess PV. Both MFAs and MR imaging planimetry require adjustments for optimized PV accuracy when compared with prostatectomy specimens.

Comparison of 12-core versus 8-core prostate biopsy: multivariate analysis of large series of US veterans

OBJECTIVES

To investigate the impact of additional biopsy cores on prostate cancer diagnosis among US veterans. The reported rate of positive biopsy results varies from 20% to 40%.

METHODS

We analyzed 1546 consecutive initial prostate biopsy procedures (8-core and 12-core biopsy protocols) at the Atlanta VA Medical Center. Both biopsy protocols targeted the peripheral zone. Cancer detection rates were compared between the 2 protocols in univariate and multivariate analyses with results expressed as odds ratios and corresponding 95% confidence intervals. Characteristics of cancer detected were also compared. Sensitivity analyses were performed for different population subgroups.

RESULTS

The overall positive biopsy rate was 49.9%, 51.2% in the 8-core group and 49.2% in the 12-core group. There was no difference between the 2 biopsy groups (adjusted odds ratio = 0.97, 95% confidence interval = 0.76-1.25). Advanced age and high body mass index were significantly associated with higher likelihood of prostate cancer, whereas larger prostate volumes were associated with lower risk.

CONCLUSIONS

In this large series of prostate biopsy procedures, in which the peripheral zone was well targeted, there was no evidence that 12-core biopsy improved the likelihood of prostate cancer diagnosis compared with 8-core biopsy. As such, the results of this cohort from a US veteran population suggest that targeting the peripheral zone is more important than the absolute number of biopsy cores. However, in certain subgroups of patients with specific clinical characteristics, such as those with very large prostates, more cores may be required. Further studies are needed to identify such characteristics.

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.

The impact of core biopsy fragmentation in prostate cancer

OBJECTIVES

Since accurate tumor localization and quantification are essential requisites avoiding prostate cancer overtreatment, we analyzed the impact of core fragmentation and the relation between core biopsy taken and pathological information in regard to cancer extension and aggressiveness (Gleason score).

METHODS

One hundred and ninety-nine men submitted to trans-rectal prostate biopsy by the same urologist between October 2006 and October 2008 were included, and the number of cores obtained by biopsy compared to the number of cores examined by the same pathologist.

RESULTS

Total core number obtained by biopsy was 21.54 (± 3.56) compared to 24.08 (± 4.77) examined by the pathologist, P < 0.01. Dividing prostate gland by areas such as base, mid and apical right and left, all areas showed statistically different core number between biopsy and pathological examination report (P < 0.01). Mean ratio of positive core cancer length was 0.41 (± 0.12) and 0.32 (± 0.8) comparing individual and overall cores analysis, respectively (P < 0.01). The mean Gleason score in the individual and overall cores analysis were 6.6 (6-9) and 6.3 (6-9), respectively, P < 0.01.

CONCLUSIONS

Considering the ongoing trend for earlier diagnosis of increasing numbers of younger men with low-risk prostate cancer, this study is original and demonstrates the possibility of core fragmentation, explaining in part over- and under-staging. One core per container and an overall Gleason score and percentage of adenocarcinoma for each container are encouraged.

Magnetic resonance imaging guided prostate biopsy in men with repeat negative biopsies and increased prostate specific antigen

PURPOSE

Undetected cancer in repeat transrectal ultrasound guided prostate biopsies in patients with increased prostate specific antigen greater than 4 ng/ml is a considerable concern. We investigated the tumor detection rate of tumor suspicious regions on multimodal 3 Tesla magnetic resonance imaging and subsequent magnetic resonance imaging guided biopsy in 68 men with repeat negative transrectal ultrasound guided prostate biopsies. We compared results to those in a matched transrectal ultrasound guided prostate biopsy population. Also, we determined the clinical significance of detected tumors.

MATERIALS AND METHODS

A total of 71 consecutive patients with prostate specific antigen greater than 4 ng/ml and 2 or greater negative transrectal ultrasound guided prostate biopsy sessions underwent multimodal 3 Tesla magnetic resonance imaging. In 68 patients this was followed by magnetic resonance imaging guided biopsy directed toward tumor suspicious regions. A matched multisession transrectal ultrasound guided prostate biopsy population from our institutional database was used for comparison. The clinical significance of detected tumors was established using accepted criteria, including prostate specific antigen, Gleason grade, stage and tumor volume.

RESULTS

The tumor detection rate of multimodal 3 Tesla magnetic resonance imaging guided biopsy was 59% (40 of 68 cases) using a median of 4 cores. The tumor detection rate was significantly higher than that of transrectal ultrasound guided prostate biopsy in all patient subgroups (p <0.01) except in those with prostate specific antigen greater than 20 ng/ml, prostate volume greater than 65 cc and prostate specific antigen density greater than 0.5 ng/ml/cc, in which similar rates were achieved. Of the 40 patients with identified tumors 37 (93%) were considered highly likely to harbor clinically significant disease.

CONCLUSIONS

Multimodal magnetic resonance imaging is an effective technique to localize prostate cancer. Magnetic resonance imaging guided biopsy of tumor suspicious regions is an accurate method to detect clinically significant prostate cancer in men with repeat negative biopsies and increased prostate specific antigen.

Systematic lateral prostate biopsy--are the benefits worth the costs?

PURPOSE

We quantified the additional benefit of routinely adding 4 lateral biopsies to the initial sextant and transrectal ultrasound lesion targeted biopsy pattern in terms of cancer detection. We related this to costs.

MATERIALS AND METHODS

Prospective data were accrued on 1,010 consecutive patients referred for initial transrectal ultrasound directed prostate biopsy between June 16, 2000 and September 1, 2005. Costs were estimated for the pathology and clinical departments in terms of staff time.

RESULTS

Of 1,010 patients 494 (48.9%) were diagnosed with prostate adenocarcinoma. In these cases 411 cancers (83%) were found in medial samples, including 107 (22%) isolated to medial cores alone and 304 (62%) in medial and lateral cores. Only 55 patients (5.4%) had cancer isolated to systematic lateral cores. Of these cancers 30 (3%) were defined as clinically significant based on Gleason grade 7 or greater, or Gleason grade 6 involving more than 5% of any core. There was a 24% increase in biopsy related costs and a 36% increase in pathology costs associated with the 4 additional lateral biopsies.

CONCLUSIONS

Medial sextant and targeted biopsy directed at transrectal ultrasound identified lesions detects 94.6% of the prostate cancer that is detected with a 10 core biopsy protocol. The latter detects an extra 3% of clinically significant prostate cancer, while increasing costs by 30%. It is important to consider the absolute benefits of systematic lateral prostate biopsy in light of this additional expense when selecting an appropriate transrectal ultrasound biopsy regimen for a patient suspected of harboring prostate cancer.

Preoperative prediction of multifocal prostate cancer and application of focal therapy: review 2007

Prostate cancer is a leading malignancy among men. Early prostate cancer is most commonly treated with radical surgery and radiotherapy. In the era of prostate-specific antigen and newly emerging highly specific screening tests, a greater number of men are given a diagnosis earlier in life, and disease is more often confined. Less-invasive treatments, such as focal therapy, are becoming increasingly popular, yielding shorter hospital stays, faster recovery, and fewer complications. Potential drawbacks to focal therapy include the risk of incomplete treatment, which may result from missed cancer foci and inadequate ablation to target tissues. Furthermore, this approach is not universally applicable to all patients--for example, those who have periurethral and extraprostatic extension of the tumor may not benefit from focal treatment. This article reviews the importance of multifocal prostate cancer and the application of focal treatment.

High yield of saturation prostate biopsy for patients with previous negative biopsies and small prostates

OBJECTIVES

Men with previously negative prostate biopsies but continued suspicion for carcinoma present a diagnostic dilemma often managed by saturation prostate biopsy (SPB). We sought to determine the patient characteristics for which repeat biopsy by SPB provides the greatest utility for prostate cancer detection.

METHODS

The records of the men at the state hospital and affiliated Veterans Affairs Medical Center with previously negative prostate biopsy findings who had then undergone SPB were reviewed. The predictors of cancer were analyzed, and those that were significant were included in a multivariate logistic regression model.

RESULTS

A total of 82 men underwent SPB from November 2001 to March 2006. Their mean age was 61 years (range 43 to 76), and 44 (54%) were white, 37 (45%) were African American, and 1 (1%) was Asian. The mean prostate-specific antigen level at SPB was 9.1 ng/mL (range 1.0 to 34). The number of prior biopsies was one in 43 patients (52%) and two or more in 39 patients (47%). The prostate volume averaged 53 cm(3) (range 12 to 200). SPB included a median of 24 cores (range 24 to 40). Of the 82 patients, 16 (19.5%) were diagnosed with cancer, of whom 10 (63%) elected to undergo radical prostatectomy. The only significant predictors of prostate cancer were the prostate-specific antigen level (P = 0.009) and prostate volume. The cancer detection rate was 57% for patients with a prostate volume less than 37 cm(3) and 7% for those with larger glands, and the difference was significant on multivariate analysis (odds ratio 31, 95% confidence interval 6 to 158, P <0.0001).

CONCLUSIONS

The results of our study have shown that SPB is an effective diagnostic tool with a high yield for men with persistent suspicion for prostate cancer, prior negative biopsy findings, and a prostate volume less than 37 cm(3).

Development and External Validation of an Extended 10-Core Biopsy Nomogram

OBJECTIVES

To test the accuracy of a previously externally validated sextant biopsy nomogram in referred men exposed to > or =10 or more biopsy cores. Moreover, we explored the hypothesis that a more accurate predictive tool could be developed.

METHODS

Previous nomogram predictors (age, digital rectal examination, prostate-specific antigen, and percent free PSA) were used to assess the accuracy of our previous nomogram in a cohort consisting of 2900 men referred for prostatic evaluation. Moreover, these variables were complemented with sampling density (SD) (i.e., ratio of gland volume and the number of planned biopsy cores) within multivariable logistic regression models (LRM) predicting presence of prostate cancer (pCA) on the initial 10 or more core biopsy. The LRMs were used to develop and internally validate (200 bootstrap resamples) a new nomogram in 1162 men from Hamburg, Germany. The LRMs' external validity was tested in three separate cohorts (Hamburg, n=582; Milan, n=961; Seattle, n=195).

RESULTS

The contemporary external validation of the previously validated sextant nomogram demonstrated 70% accuracy. Internal validation of the new nomogram demonstrated 77% accuracy, and external cohorts demonstrated 73-76% accuracy.

CONCLUSIONS

In the era of extended biopsy schemes, previously developed predictive models are less accurate in predicting the probability of pCA on initial biopsy. We developed a new tool that allows obtaining more accurate predictions. Moreover, before biopsy, it also allows defining the ideal ratio between gland volume and the number of planned biopsy cores that would yield the ideal biopsy rate.

Hormonal Predictors of Prostate Cancer

INTRODUCTION

Androgens are necessary for the development and functioning of the prostate gland. The association of serum testosterone and pituitary hormone levels with prostate cancer development is not completely understood. In this clinical study, we evaluated the role of serum testosterone, free testosterone, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels in predicting prostate cancer risk in patients who had transrectal ultrasonography-guided prostate biopsy with the suspicion of prostate cancer.

MATERIAL AND METHODS

A total of 211 patients who were selected to undergo prostatic biopsy due to abnormal digital rectal examination and/or a serum prostate-specific antigen (PSA) level >2.5 ng/ml were included in the study. The patient characteristics of total PSA, free/total PSA ratio, serum total testosterone, free testosterone, free/total testosterone ratio, FSH and LH levels were compared according to the pathological diagnosis.

RESULTS

The mean age was 63.91 years (range 44-83) and the mean PSA level was 9.23 ng/ml (range 0.13-50.41) in the whole group. Of 211 patients, 69 (32.7%) were positive for prostate cancer. The patients who were positive for prostate cancer had statistically lower levels of serum total testosterone compared with the patients who were diagnosed as having benign prostatic hyperplasia (BPH; 405 vs. 450.5 ng/dl, respectively; p = 0.013). The serum FSH level was significantly higher in men with prostatic cancer than in men with BPH (7.56 vs. 6.06 mIU/ml, respectively; p = 0.029). No significant differences between men with prostatic cancer and those with BPH were found for serum LH levels. When normal ranges for serum free and total testosterone levels were defined as 9 pg/ml and 300 ng/dl, respectively, patients who had low free testosterone and total testosterone levels had significantly higher cancer detection rates than patients with high serum androgen levels: 40.8% (40/98) versus 25.6% (29/113) (p = 0.021), and 48.6% (18/37) versus 29.3% (51/174), respectively (p = 0.023). After logistic regression analysis, none of the hormones showed a significant difference in predicting the risk of prostate cancer in patients undergoing prostate biopsy with suspicion of the disease.

CONCLUSION

Our data suggest that patients diagnosed with prostate cancer have low levels of serum testosterone and high levels of serum FSH compared with the patients with BPH. No support was found for the theory that high levels of testosterone increase prostate cancer risk. Further studies are needed to clarify the relationship between hormones and prostate cancer etiology.

Optimal site and number of biopsy cores according to prostate volume prostate cancer detection in Korea

OBJECTIVES

To compare different biopsy schemes for detecting prostate cancer in Korean men.

METHODS

A total of 516 men, 40 to 79 years old (mean 64.1 +/- 7.8), constituted the study cohort. The patients were divided to quartiles according to prostate volume: 10 to 30, 30.1 to 40, 40.1 to 55, and 55.1 to 162 cm3.

RESULTS

The cancer detection rates decreased as the prostate volume increased in the quartiles used (P = 0.001). The group-specific cancer detection rate was 20.0% to 23.8%, 22.1% to 25.6%, 23.6% to 26.6%, and 27.7% in the 6, 8, 10, and 12-core groups, respectively. In all patients undergoing sextant biopsy, laterally placed cores, including the apex, lateral mid-gland, and lateral base, seemed as optimal as the six-core biopsy scheme. The unique cancer detection rates of each biopsy region were low in all patients groups and were not significantly different according to prostate volume quartile. Of the patients with suspicious lesions on transrectal ultrasonography, no cancer was present only in the lesion-directed biopsies, even if sextant biopsy technique was used.

CONCLUSIONS

Our data have shown that lower core schemes can be used with results almost similar to those using the 12-core protocol in this population. A laterally placed, six-core technique is an appropriate biopsy scheme in patients with a prostate volume of less than 40 cm3. Transrectal ultrasound-directed biopsies can be omitted even when using six-core biopsy protocols because the yield of these biopsies was low. Prebiopsy transrectal ultrasonography is unnecessary because the prostate volume estimation can be done at the same time as the biopsy.

Quantifying the Impact of Prostate Volumes, Number of Biopsy Cores and 5α-Reductase Inhibitor Therapy on the Probability of Prostate Cancer Detection Using Mathematical Modeling

PURPOSE

Previous studies demonstrated a negative correlation between prostate volume and biopsy yield. By decreasing prostate volume 5alpha-reductase inhibitors may enhance cancer detection, which may explain the greater detection of high grade tumors in the finasteride arm of the Prostate Cancer Prevention Trial.

MATERIALS AND METHODS

A mathematical model was constructed to analyze the effects of prostate and tumor volumes, and biopsy core number on cancer detection. The effects of the volume reduction observed with finasteride in the Prostate Cancer Prevention Trial were also modeled, as was the potential reduction in tumor volume needed to explain the observed difference in prostate cancer detection. The model was also applied to the Reduction by Dutasteride of Prostate Cancer Events study.

RESULTS

A higher number of biopsies are required to ensure a detection probability of 0.90 or greater in larger glands or with smaller tumors. In the Prostate Cancer Prevention Trial for a tumor volume of 1 cc a 17% increase in the detection rate in the finasteride arm would be predicted if there was no change in tumor volume, likewise the rate would be 11% to 17% for the dutasteride arm of the Reduction by Dutasteride of Prostate Cancer Events study. The calculated reduction in tumor volume needed to explain the difference in cancer detection between the finasteride and placebo arms of the Prostate Cancer Prevention Trial would be 51% to 66%.

CONCLUSIONS

This model provides guidance on the optimal number of biopsy cores that accord with an earlier model. These findings also suggest that, if there were no reduction in tumor volume, 5alpha-reductase inhibitor therapy could lead to excess cancer detection, including high grade tumors.

The effect of prior biopsy scheme on prostate cancer detection for repeat biopsy population: results of the 14-core prostate biopsy technique

OBJECTIVES

To evaluate the diagnostic performance of 14-core repeat biopsy protocol and the impact of prior biopsy scheme on repeat prostate biopsy group.

METHODS

211 patients had repeat biopsy using 14-core protocol consisting of 10-core peripheral zone (classical sextant+4 lateral peripheral cores) and 4-core transitional zone (TZ) biopsies. The diagnostic yield was determined both in patients who had previously undergone sextant or 10-core biopsy protocol.

RESULTS

Overall cancer detection rate was 25.6%. 14-core biopsy technique detected cancer in 36.1 and 18.7% of the patients who had a previous sextant biopsy and 10-core biopsy protocol, respectively (P = 0.005). Patients with and without high-grade prostatic intraepithelial neoplasia (HGPIN) in the previous sextant biopsy had 56.5 and 28.3% cancer detection rates on the subsequent extended biopsy, respectively (P = 0.017) Patients who had previous 10-core biopsy with and without HGPIN revealed 22.9 and 17.2% cancer detection rates, respectively (P = 0.465) Additional four lateral peripheral cores detected 33% (3/30) and 17% (4/24) of cancers in patients with previous sextant and 10-core biopsy, respectively. 3.7% of the patients had tumor only in the TZ and none of them had prior extended biopsy.

CONCLUSIONS

The yield of extended 14-core repeat biopsy protocol was higher in patients with previous negative sextant biopsy compared to the patients with previous negative 10-core biopsy. HGPIN history found on previous sextant biopsy was a strong cancer predictor on repeat biopsy; same was not true for the patients with previous 10-core biopsy. The yield of lateral peripheral cores and TZ biopsies were lower in patients with prior negative extended biopsy.

Serum ribonuclease activity in the diagnosis of prostate cancer in men with serum prostate-specific antigen levels between 2.5 and 20 ng/mL

OBJECTIVES

To evaluate the diagnostic value of serum ribonuclease activity for prostate cancer detection and to compare its performance with serum PSA.

DESIGN AND METHODS

111 subjects with serum PSA levels between 2.5 and 20 ng/mL underwent prostate biopsy. The diagnostic performance of serum ribonuclease activity, PSA, free PSA, complex PSA and PSA derivatives was studied in regard to discriminating prostate cancer from BPH.

RESULTS

Of 111 patients, 27 (24.3%) were positive for prostate cancer. Median serum ribonuclease level in patients with prostate cancer was significantly higher than the non-cancer patients (21.3 U/mL vs. 6.6 U/mL, P < 0.001). Area under curve (AUC) values for ribonuclease activity level, PSA, f/tPSA and cPSA were 0.696, 0.514, 0.617 and 0.662, respectively. Of 27 patients with prostate cancer, radical prostatectomy was performed in 15. Of these 15 cases, four (26.7%) had clinical insignificant tumors; all with undetectable serum ribonuclease activity. When median values of various diagnostic parameters were compared in regard to predicting clinically significant and insignificant cancers, only serum ribonuclease activity was found to be significant.

CONCLUSIONS

Although serum ribonuclease activity had no additional benefit beyond serum PSA in the diagnosis of patients with PSA levels between 2.5 and 20 ng/mL, it may be helpful to discriminate the clinically significant prostate cancers and thus select the proper treatment accordingly.