Prostate Cancers Diagnosed at Repeat Biopsy are Smaller and Less Likely to be High Grade

PSA, an outdated biomarker for prostate cancer: in search of a more specific biomarker, citrate takes the spotlight

The prevailing biomarker employed for prostate cancer (PCa) screening and diagnosis is the prostate-specific antigen (PSA). Despite excellent sensitivity, PSA lacks specificity, leading to false positives, unnecessary biopsies and overdiagnosis. Consequently, PSA is increasingly less used by clinicians, thus underscoring the imperative for the identification of new biomarkers. An emerging biomarker in this context is citrate, a molecule secreted by the normal prostate, which has been shown to be inversely correlated with PCa. Here, we discuss about PSA and its usage for PCa diagnosis, its lack of specificity, and the various conditions that can affect its levels. We then provide our vision about what we think would be a valuable addition to our PCa diagnosis toolkit, citrate. We describe the unique citrate metabolic program in the prostate and how this profile is reprogrammed during carcinogenesis. Finally, we summarize the evidence that supports the usage of citrate as a biomarker for PCa diagnosis, as it can be measured in various patient samples and be analyzed by several methods. The unique relationship between citrate and PCa, combined with the stability of citrate levels in other prostate-related conditions and the simplicity of its detection, further accentuates its potential as a biomarker.

Development and Validation of an 18-Gene Urine Test for High-Grade Prostate Cancer

Importance

Benefits of prostate cancer (PCa) screening with prostate-specific antigen (PSA) alone are largely offset by excess negative biopsies and overdetection of indolent cancers resulting from the poor specificity of PSA for high-grade PCa (ie, grade group [GG] 2 or greater).

Objective

To develop a multiplex urinary panel for high-grade PCa and validate its external performance relative to current guideline-endorsed biomarkers.

Design, Setting, and Participants

RNA sequencing analysis of 58 724 genes identified 54 markers of PCa, including 17 markers uniquely overexpressed by high-grade cancers. Gene expression and clinical factors were modeled in a new urinary test for high-grade PCa (MyProstateScore 2.0 [MPS2]). Optimal models were developed in parallel without prostate volume (MPS2) and with prostate volume (MPS2+). The locked models underwent blinded external validation in a prospective National Cancer Institute trial cohort. Data were collected from January 2008 to December 2020, and data were analyzed from November 2022 to November 2023.

Exposure

Protocolized blood and urine collection and transrectal ultrasound-guided systematic prostate biopsy.

Main Outcomes and Measures

Multiple biomarker tests were assessed in the validation cohort, including serum PSA alone, the Prostate Cancer Prevention Trial risk calculator, and the Prostate Health Index (PHI) as well as derived multiplex 2-gene and 3-gene models, the original 2-gene MPS test, and the 18-gene MPS2 models. Under a testing approach with 95% sensitivity for PCa of GG 2 or greater, measures of diagnostic accuracy and clinical consequences of testing were calculated. Cancers of GG 3 or greater were assessed secondarily.

Results

Of 761 men included in the development cohort, the median (IQR) age was 63 (58-68) years, and the median (IQR) PSA level was 5.6 (4.6-7.2) ng/mL; of 743 men included in the validation cohort, the median (IQR) age was 62 (57-68) years, and the median (IQR) PSA level was 5.6 (4.1-8.0) ng/mL. In the validation cohort, 151 (20.3%) had high-grade PCa on biopsy. Area under the receiver operating characteristic curve values were 0.60 using PSA alone, 0.66 using the risk calculator, 0.77 using PHI, 0.76 using the derived multiplex 2-gene model, 0.72 using the derived multiplex 3-gene model, and 0.74 using the original MPS model compared with 0.81 using the MPS2 model and 0.82 using the MPS2+ model. At 95% sensitivity, the MPS2 model would have reduced unnecessary biopsies performed in the initial biopsy population (range for other tests, 15% to 30%; range for MPS2, 35% to 42%) and repeat biopsy population (range for other tests, 9% to 21%; range for MPS2, 46% to 51%). Across pertinent subgroups, the MPS2 models had negative predictive values of 95% to 99% for cancers of GG 2 or greater and of 99% for cancers of GG 3 or greater.

Conclusions and Relevance

In this study, a new 18-gene PCa test had higher diagnostic accuracy for high-grade PCa relative to existing biomarker tests. Clinically, use of this test would have meaningfully reduced unnecessary biopsies performed while maintaining highly sensitive detection of high-grade cancers. These data support use of this new PCa biomarker test in patients with elevated PSA levels to reduce the potential harms of PCa screening while preserving its long-term benefits.

MyProstateScore in men considering repeat biopsy: validation of a simple testing approach

BACKGROUND

Men with persistent risk of Grade Group (GG) ≥ 2 cancer after a negative biopsy present a unique clinical challenge. The validated MyProstateScore test is clinically-available for pre-biopsy risk stratification. In biopsy-naïve patients, we recently validated a straightforward testing approach to rule-out GG ≥ 2 cancer with 98% negative predictive value (NPV) and 97% sensitivity. In the current study, we established a practical MPS-based testing approach in men with a previous negative biopsy being considered for repeat biopsy.

METHODS

Patients provided post-digital rectal examination urine prior to repeat biopsy. MyProstateScore was calculated using the validated, locked model including urinary PCA3 and TMPRSS2:ERG scores with serum PSA. In a clinically-appropriate primary (i.e., training) cohort, we identified a lower (rule-out) threshold approximating 90% sensitivity and an upper (rule-in) threshold approximating 80% specificity for GG ≥ 2 cancer. These thresholds were applied to an external validation cohort, and performance measures and clinical outcomes associated with their use were calculated.

RESULTS

MyProstateScore thresholds of 15 and 40 met pre-defined performance criteria in the primary cohort (422 patients; median PSA 6.4, IQR 4.3-9.1). In the 268-patient validation cohort, 25 men (9.3%) had GG ≥ 2 cancer on repeat biopsy. The rule-out threshold of 15 provided 100% NPV and sensitivity for GG ≥ 2 cancer and would have prevented 23% of unnecessary biopsies. Use of MyProstateScore >40 to rule-in biopsy would have prevented 67% of biopsies while maintaining 95% NPV. In the validation cohort, the prevalence of GG ≥ 2 cancer was 0% for MyProstateScore 0-15, 6.5% for MyProstateScore 15-40, and 19% for MyProstateScore >40.

CONCLUSIONS

In patients who previously underwent a negative prostate biopsy, the MyProstateScore values of 15 and 40 yielded clinically-actionable rule-in and rule-out risk groups. Using this straightforward testing approach, MyProstateScore can meaningfully inform patients and physicians weighing the need for repeat biopsy.

Standardized prostate cancer incidence and mortality rates following initial non-malignant biopsy result

OBJECTIVES

To compare the incidence of subsequent prostate cancer diagnosis and death following an initial non-malignant systematic transrectal ultrasonography (TRUS) biopsy with that in an age- and calendar-year matched population over a 20-year period.

SUBJECTS AND METHODS

This population-based analysis compared a cohort of all men with initial non-malignant TRUS biopsy in Denmark between 1995 and 2016 (N = 37 231) with the Danish population matched by age and calendar year, obtained from the NORDCAN 9.1 database. Age- and calendar year-corrected standardized prostate cancer incidence (SIR) and prostate cancer-specific mortality ratios (SMRs) were calculated and heterogeneity among age groups was assessed with the Cochran's Q test.

RESULTS

The median time to censoring was 11 years, and 4434 men were followed for more than 15 years. The corrected SIR was 5.2 (95% confidence interval [CI] 5.1-5.4) and the corrected SMR was 0.74 (95% CI 0.67-0.81). Estimates differed among age groups (P < 0.001 for both), with a higher SIR and SMR among younger men.

CONCLUSION

Men with non-malignant TRUS biopsy have a much higher incidence of prostate cancer but a risk of prostate cancer death below the population average. This underlines that the oncological risk of cancers missed in the initial TRUS biopsy is low. Accordingly, attempts to increase the sensitivity of initial biopsy are unjustified. Moreover, current follow-up after non-malignant biopsy is likely to be overaggressive, particularly in men over the age of 60 years.

Biparametric Magnetic Resonance Imaging-Derived Nomogram to Detect Clinically Significant Prostate Cancer by Targeted Biopsy for Index Lesion

BACKGROUND

Currently, it is necessary to investigate how to combine biparametric magnetic resonance imaging (bpMRI) with various clinical parameters for the detection of clinically significant prostate cancer (csPCa).

PURPOSE

To develop a multivariate prebiopsy nomogram using clinical and bpMRI parameters for estimating the probability of csPCa.

STUDY TYPE

Retrospective, single-center study.

SUBJECTS

Two hundred and twenty-six patients who underwent targeted biopsy (TBx) for the MRI-suspected index lesion because of clinical suspicions of PCa.

FIELD STRENGTH/SEQUENCE

A 3 T MRI including turbo spin-echo T₂ -weighted and diffusion-weighted single-shot echo-planar imaging sequences.

ASSESSMENT

Prebiopsy clinical and bpMRI parameters were patient age, biopsy history (biopsy-naïve or repeated biopsy status), prostate-specific antigen density (PSAD), Prostate Imaging-Reporting and Data System version 2.1 (PI-RADSv2.1), and apparent diffusion coefficient ratio (ADCR). ADCR was defined as mean ADC of the index lesion divided by mean ADC of the contralateral prostatic region. A multivariate prebiopsy nomogram for csPCa (i.e. Gleason sum ≥7) was developed. Area under the curve (AUC) of each parameter and prebiopsy nomogram was assessed. Five-fold cross-validation was performed for robust estimation of performance of the prebiopsy nomogram.

STATISTICAL TESTS

Logistic regression, receiver-operating curve, and 5-fold cross-validation. P-value < 0.05 was considered statistically significant.

RESULTS

Proportion of csPCa was 31.9% (72/226). The AUCs of age, biopsy-naïve status, PSAD, PI-RADSv2.1, ADCR, and prebiopsy nomogram were 0.657 (95% confidence interval [CI], 0.580-0.733), 0.593 (95% CI, 0.525-0.660), 0.762 (95% CI, 0.697-0.826), 0.824 (95% CI, 0.770-0.878), 0.829 (95% CI, 0.769-0.888), and 0.906 (95% CI, 0.863-0.948), respectively: AUC of nomogram was significantly different than that of individual parameter. In the 5-fold cross-validation, the mean AUC of the prebiopsy nomogram for csPCa was 0.888 (95% CI, 0.786-0.983).

DATA CONCLUSIONS

This multivariate prebiopsy nomogram using clinical and bpMRI parameters may help estimate the probability of csPCa in patients undergoing TBx. ADCR seems to enhance the role of bpMRI in detecting csPCa.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

Detection of Clinically Significant Prostate Cancer by Systematic TRUS-Biopsies in a Population-Based Setting Over a 20 Year Period

OBJECTIVE

To assess the performance of systematic TRUS-biopsies in a population-based setting to detect clinically significant PCa (csPCa) in combination with age, clinical tumor category (cT), and prostate-specific antigen (PSA) in men referred for the first biopsy.

METHODS

We identified all men referred for PCa work-up because of elevated PSA who underwent initial TRUS-biopsies in the nationwide Danish Prostate Cancer Registry (DaPCaR) between January 1st, 1995 and December 31st, 2016, in Denmark. Risk of histologic findings in initial TRUS-biopsies categorized as non-malignant, insignificant PCa, or significant PCa (csPCa). We defined csPCa as any biopsy containing Gleason score 3 + 4 or above as in the PRECISION trial. We assessed risk of csPCa with absolute risk, logistic regression model, and predicted risks.

RESULTS AND LIMITATIONS

After exclusions, our cohort included 39,886 men. The diagnostic hit rate for csPCa was 40.8 %. Men with PSA > 20 ng/mL and ≥cT2 harbor a risk >75% for finding csPCa in the first TRUS biopsy-set. Men with cT1 tumors and PSA < 20 ng/mL have a risk of non-malignant histology of at least 58%. Limitations include the high number of exclusions based on missing information.

CONCLUSION

The diagnostic accuracy of systematic TRUS-biopsies is high for men with palpable tumors and high PSA. Our data point to the fact that not all men need pre-biopsy MRI to find csPCa.

What is the risk of prostate cancer mortality following negative systematic TRUS-guided biopsies? A systematic review

OBJECTIVE

To investigate the risk of prostate cancer-specific mortality (PCSM) following initial negative systematic transrectal ultrasound-guided (TRUS) prostate biopsies.

DESIGN

Systematic review.

DATA SOURCES

PubMed and Embase were searched using a string combination with keywords/Medical Subject Headings terms and free text in the search builder. Date of search was 13 April 2020.

STUDY SELECTION

Studies addressing PCSM following initial negative TRUS biopsies. Randomised controlled trials and population-based studies including men with initial negative TRUS biopsies reported in English from 1990 until present were included.

DATA EXTRACTION

Data extraction was done using a predefined form by two authors independently and compared with confirm data; risk of bias was assessed using the Newcastle-Ottawa Scale for cohort studies when applicable.

RESULTS

Four eligible studies were identified. Outcomes were reported differently in the studies as both cumulative incidence and Kaplan-Meier estimates have been used. Regardless of the study differences, all studies reported low estimated incidence of PCSM of 1.8%-5.2% in men with negative TRUS biopsies during the following 10-20 years. Main limitation in all studies was limited follow-up.

CONCLUSION

Only a few studies have investigated the risk of PCSM following initial negative biopsies and all studies included patients before the era of MRI of the prostate. However, the studies point to the fact that the risk of PCSM is low following initial negative TRUS biopsies, and that the level of prostate-specific antigen before biopsies holds prognostic information. This may be considered when advising patients about the need for further diagnostic evaluation.

PROSPERO REGISTRATION NUMBER

CRD42019134548.

MultiParametric Magnetic Resonance Imaging-Based Nomogram for Predicting Prostate Cancer and Clinically Significant Prostate Cancer in Men Undergoing Repeat Prostate Biopsy

OBJECTIVE

To develop and internally validate nomograms based on multiparametric magnetic resonance imaging (mpMRI) to predict prostate cancer (PCa) and clinically significant prostate cancer (csPCa) in patients with a previous negative prostate biopsy.

MATERIALS AND METHODS

The clinicopathological parameters of 231 patients who underwent a repeat systematic prostate biopsy and mpMRI were reviewed. Based on Prostate Imaging and Reporting Data System, the mpMRI results were assigned into three groups: Groups "negative," "suspicious," and "positive." Two clinical nomograms for predicting the probabilities of PCa and csPCa were constructed. The performances of nomograms were assessed using area under the receiver operating characteristic curves (AUCs), calibrations, and decision curve analysis.

RESULTS

The median PSA was 15.03 ng/ml and abnormal DRE was presented in 14.3% of patients in the entire cohort. PCa was detected in 75 patients (32.5%), and 59 (25.5%) were diagnosed with csPCa. In multivariate analysis, age, prostate-specific antigen (PSA), prostate volume (PV), digital rectal examination (DRE), and mpMRI finding were significantly independent predictors for PCa and csPCa (all p < 0.01). Of those patients diagnosed with PCa or csPCa, 20/75 (26.7%) and 18/59 (30.5%) had abnormal DRE finding, respectively. Two mpMRI-based nomograms with super predictive accuracy were constructed (AUCs = 0.878 and 0.927, p < 0.001), and both exhibited excellent calibration. Decision curve analysis also demonstrated a high net benefit across a wide range of probability thresholds.

CONCLUSION

mpMRI combined with age, PSA, PV, and DRE can help predict the probability of PCa and csPCa in patients who underwent a repeat systematic prostate biopsy after a previous negative biopsy. The two nomograms may aid the decision-making process in men with prior benign histology before the performance of repeat prostate biopsy.

Management of men with previous negative prostate biopsy

PURPOSE OF REVIEW

Up to 70% of prostate biopsies are negative in men with suspected prostate cancer. Because of inherent limitations in biopsy strategies, a significant proportion of cancers are missed on initial biopsy. Following negative biopsy, men frequently exhibit persistently elevated prostate-specific antigen - raising concerns for missed diagnosis. We highlight the recent updates in the management of negative prostate biopsy.

RECENT FINDINGS

Advances in noninvasive diagnostics are available and assist clinicians in further substratifying risk of prostate cancer. Despite limited data, urinary prostate cancer antigen 3 and transmembrane protease serine 2 appear to have a promising predictive value for patients suspected of prostate cancer. The advent of multiparametricMRI allows the visualization of intermediate and high-grade prostate cancer, particularly in the troublesome anterior prostate. This modality may further provide the potential for magnetic resonance-guided targeted biopsies. Current data suggest that in the presence of suspicious radiological findings, magnetic resonance-guided biopsies have superior sensitivity profiles compared with traditional rebiopsy approaches. In the absence of multiparametricMRI or suspicious findings, traditional saturation biopsies are sufficient.

SUMMARY

The management of negative biopsies is evolving rapidly with emerging diagnostics to stratify risk of prostate cancer in men with previous negative biopsies. An increasing body of information supports the use of magnetic resonance-guided biopsies.

Biomarker potential of ST6GALNAC3 and ZNF660 promoter hypermethylation in prostate cancer tissue and liquid biopsies

Current diagnostic and prognostic tools for prostate cancer (PC) are suboptimal, leading to overdiagnosis and overtreatment. Aberrant promoter hypermethylation of specific genes has been suggested as novel candidate biomarkers for PC that may improve diagnosis and prognosis. We here analyzed ST6GALNAC3 and ZNF660 promoter methylation in prostate tissues, and ST6GALNAC3,ZNF660,CCDC181, and HAPLN3 promoter methylation in liquid biopsies. First, using four independent patient sample sets, including a total of 110 nonmalignant (NM) and 705 PC tissue samples, analyzed by methylation‐specific qPCR or methylation array, we found that hypermethylation of ST6GALNAC3 and ZNF660 was highly cancer‐specific with areas under the curve (AUC) of receiver operating characteristic (ROC) curve analysis of 0.917–0.995 and 0.846–0.903, respectively. Furthermore, ZNF660 hypermethylation was significantly associated with biochemical recurrence in two radical prostatectomy (RP) cohorts of 158 and 392 patients and remained significant also in the subsets of patients with Gleason score ≤7 (univariate Cox regression and log‐rank tests, P < 0.05), suggesting that ZNF660 methylation analysis can potentially help to stratify low‐/intermediate‐grade PCs into indolent vs. more aggressive subtypes. Notably, ZNF660 hypermethylation was also significantly associated with poor overall and PC‐specific survival in the RP cohort (n = 158) with long clinical follow‐up available. Moreover, as proof of principle, we successfully detected highly PC‐specific hypermethylated circulating tumor DNA (ctDNA) for ST6GALNAC3,ZNF660,HAPLN3, and CCDC181 in liquid biopsies (serum) from 27 patients with PC vs. 10 patients with BPH, using droplet digital methylation‐specific PCR analysis. Finally, we generated a three‐gene (ST6GALNAC3/CCDC181/HAPLN3) ctDNA hypermethylation model, which detected PC with 100% specificity and 67% sensitivity. In conclusion, we here for the first time demonstrate diagnostic biomarker potential of ST6GALNAC3 and ZNF660 methylation, as well as prognostic biomarker potential of ZNF660. Furthermore, we show that hypermethylation of four genes can be detected in ctDNA in liquid biopsies (serum) from patients with PC.

Risk of prostate cancer diagnosis and mortality in men with a benign initial transrectal ultrasound-guided biopsy set: a population-based study

BACKGROUND

The risk of missing prostate cancer in the transrectal ultrasound-guided systematic biopsies of the prostate in men with suspected prostate cancer is a key problem in urological oncology. Repeat biopsy or MRI-guided biopsies have been suggested to increase sensitivity for diagnosis of prostate cancer, but the risk of disease-specific mortality in men who present with raised prostate-specific antigen (PSA) concentration and a benign initial biopsy result remains unknown. We investigated the risk of overall and prostate cancer-specific mortality in men with a benign initial biopsy set.

METHODS

Data were extracted from the Danish Prostate Cancer Registry-a population-based registry including all men undergoing histopathological assessment of prostate tissue. All men who were referred for transrectal ultrasound-guided biopsy for assessment of suspected prostate cancer between Jan 1, 1995, and Dec 31, 2011, in Denmark were eligible for inclusion. Follow-up data were obtained on April 28, 2015. The primary endpoint was the cumulative incidence of prostate cancer-specific mortality, analysed in a competing risk setting, with death from other causes as the competing event.

FINDINGS

Between Jan 1, 1995, and Dec 31, 2011, 64 430 men were referred for transrectal ultrasound-guided biopsy, of whom 63 454 were eligible for inclusion. Median follow-up was 5·9 years (IQR 3·8-8·5) and the total follow-up time, from the enrolment of the first patient on Jan 1, 1995, until the extraction of causes of death on April 28, 2015, was 20 years. 10 407 (30%) of 35 159 men with malignant initial biopsy sets died from prostate cancer, compared with 541 (2%) of 27 181 men with benign initial biopsy sets. Estimated overall 20-year mortality was 76·1% (95% CI 73·0-79·2). In all men referred for transrectal ultrasound-guided biopsy, the cumulative incidence of prostate cancer-specific mortality after 20 years was 25·6% (24·7-26·5) versus 50·5% (47·5-53·5) for mortality from other causes. In men with benign initial biopsy sets, the cumulative incidence of prostate cancer-specific mortality was 5·2% (3·9-6·5) versus 59·9% (55·2-64·6) for mortality from other causes. In men with PSA concentrations 10 μg/L or lower and benign initial biopsy sets (2779 men), the cumulative incidence of prostate cancer-specific mortality was 0·7% (0·2-1·3). Cumulative incidence of prostate cancer specific mortality in men with benign initial biopsy sets was 3·6% (95% CI 0·1-7·2) for men with a PSA higher than 10 ng/mL but 20 ng/mL or less (855 men) and 17·6% (12·7-22·4) and for men with a PSA higher than 20 ng/mL (454 men).

INTERPRETATION

The first systematic transrectal ultrasound-guided biopsy set holds important prognostic information. The 20-year risk of prostate cancer-specific mortality in men with benign initial results is low. Our findings question whether men with low PSA concentration and a benign initial biopsy set should undergo further diagnostic assessment in view of the high risk of mortality from other causes.

FUNDING

Capital Region of Denmark's Fund for Health Research, Danish Cancer Society, Danish Association for Cancer Research, and Krista and Viggo Petersen's Foundation.

The Impact of Repeat Prostate Biopsies on Oncologic, Pathological and Perioperative Outcomes after Radical Prostatectomy

PURPOSE

The impact of repeat biopsy sessions on radical prostatectomy remains controversial regarding perioperative, pathological and oncologic outcome.

MATERIALS AND METHODS

We analyzed the records of 12,624 patients who underwent radical prostatectomy from 2007 to 2013. The association of the number of biopsy sessions (range 1 to 3 or more) with pathological outcomes and perioperative complications was analyzed using the Wilcoxon matched pair test. To test the association between biopsy sessions and biochemical recurrence-free survival we used Kaplan-Meier curves and multivariable Cox regression analysis.

RESULTS

Of the patients 89.2% had 1 biopsy session, 7.4% had 2 sessions and 3.4% had 3 or more sessions. Median followup was 36.6 months. In patients with 1, 2 and 3 or more biopsy sessions prostate volume (38, 44 and 45 ml) and prostate specific antigen (6.7, 7.6 and 10.1 ng/ml, respectively) were greater (each p <0.001). The perioperative outcome was more favorable. Patients with 1, 2 and 3 or more biopsy sessions more often had organ confined tumors (67.6%, 72.1% and 72.9%, p = 0.003) and higher tumor volume (3.1, 3.0 and 3.6 ml, p <0.001) but a lower tumor percent (7.5%, 3.7% and 2.4%, respectively, p <0.001). More biopsy sessions were associated with fewer lymph node metastases (1, 2 and 3 sessions 0.23, 0.13 and 0.17, respectively, p <0.001). Gleason score and surgical margin status did not differ. The overall biochemical recurrence rate was 18.9% and it was comparable among the biopsy groups. No association was found between the number of biopsies and biochemical recurrence.

CONCLUSIONS

Patients with multiple biopsy sessions experience a slightly more favorable pathological outcome without an impact on the oncologic outcome. The perioperative outcome was more favorable in patients with multiple biopsies.

Addressing the need for repeat prostate biopsy: new technology and approaches

No guidelines currently exist that address the need for rebiopsy in patients with a negative diagnosis of prostate cancer on initial biopsy sample analysis. Accurate diagnosis of prostate cancer in these patients is often complicated by continued elevation of serum PSA levels that are suggestive of prostate cancer, resulting in a distinct management challenge. Following negative initial findings of biopsy sample analysis, total serum PSA levels and serum PSA kinetics are ineffective indicators of a need for a repeat biopsy; therefore, patients suspected of having prostate cancer might undergo several unnecessary biopsy procedures. Several alternative strategies exist for identifying men who might be at risk of prostate cancer despite negative findings of biopsy sample analysis. Use of other serum PSA-related measurements enables more sensitive and specific diagnosis and can be combined with knowledge of clinicopathological features to improve outcomes. Other options include the FDA-approved Progensa(®) test and prostate imaging using MRI. Newer tissue-based assays that measure methylation changes in normal prostate tissue are currently being developed. A cost-effective strategy is proposed in order to address this challenging clinical scenario, and potential directions of future studies in this area are also described.

When prostate cancer remains undetectable: The dilemma

Since the first report on the efficacy of sextant biopsy under transrectal ultrasound guidance, there have been many modifications related to the total number of cores and the localization of biopsies to improve the prostate cancer (PCa) detection rate. The 2010 National Comprehensive Cancer Network Early PCa Detection Guidelines noted the 12-core biopsy scheme as the standard. However, this extended biopsy scheme still fails to detect 20% of high-grade PCa that can be detected by detailed pathological evaluation of radical prostatectomy; therefore, there is need for saturation biopsies. The existence of suspicions of PCa after previous negative biopsy or biopsies represents a valid indication for saturation biopsy. There has been no significant increment in morbidity or in insignificant PCa detection rates when a saturation biopsy scheme was used with an extended biopsy scheme. Along with the improvement in the PCa detection rate, accurate oncological mapping of PCa is another important consideration of saturation biopsies. The ideal number of cores and the diagnostic value of saturation biopsy after the failure of initial therapy are some of the issues that need to be addressed. Preliminary reports have shown that magnetic resonance imaging can improve the PCa detection rate, save patients from unnecessary biopsies, and decrease the need for a high number of cores; however, multiple limitations continue to exist.

Prostate Imaging Reporting and Data System and Likert Scoring System: Multiparametric MR Imaging Validation Study to Screen Patients for Initial Biopsy

PURPOSE

To compare the diagnostic performance of the magnetic resonance (MR) imaging-based Prostate Imaging Reporting and Data System (PI-RADS) and a Likert scale in the detection of prostate cancer in a cohort of patients undergoing initial prostate biopsy.

MATERIALS AND METHODS

This institutional review board-approved two-center prospective study included 118 patients with normal digital rectal examination (DRE) results but elevated prostate-specific antigen (PSA) levels (4-20 ng/mL) who were referred for initial prostate biopsies and had one suspicious (Likert scale score, ≥3) focus at prebiopsy 1.5-T multiparametric MR imaging performed with T2-weighted, diffusion-weighted [DW], and dynamic contrast material-enhanced imaging. Targeted core biopsies and random systematic core biopsies were performed. The elementary unit for analysis was the core. Relationships were assessed by using the Mann-Whitney U test. Yates corrected and Pearson χ(2) tests were used to evaluate categoric variables. A training set was randomly drawn to construct the receiver operating characteristic curves for the summed PI-RADS scores and for the Likert scale scores. The thresholds to recommend biopsy were obtained from the Youden J statistics and were tested in the remaining validation set in terms of predictive characteristics. Interobserver variability was analyzed by using weighed κ statistics in a random set of 50 patients.

RESULTS

Higher T2-weighted, DW, and dynamic contrast-enhanced imaging PI-RADS scores were observed in areas that yielded cancer-positive cores. The percentage of positive cores increased with the sum of scores aggregated in five classes as follows: For summed PI-RADS scores of 3-5, the percentage of positive cores was 2.3%; for scores of 6-8, it was 5.8%; for scores of 9 or 10, it was 24.7%; for scores of 11 or 12, it was 51.8%; and for scores of 13-15, it was 72.1% (P for trend, <.0001). For the threshold of summed PI-RADS scores of 9 or greater, sensitivity was 86.6%, specificity was 82.4%, the positive predictive value was 52.4%, the negative predictive value was 96.5%, and accuracy was 83.2%. The respective data for Likert scale scores of 3 or greater were 93.8%, 73.6%, 44.3%, 98.1%, and 73.3%. Good interobserver agreement was observed for the Likert scale (κ = 0.80) and the summed PI-RADS (κ = 0.73) scoring systems.

CONCLUSION

PI-RADS provided the site-specific stratified risk of cancer-positive cores in biopsy-naive men with normal DRE results and elevated PSA levels. There was no significant difference between summed PI-RADS scores of 9 or greater and Likert scale scores of 3 or greater in the detection of cancer in the peripheral zone.

Clinicopathologic differences between prostate cancers detected during initial and repeat transrectal ultrasound-guided biopsy in Korea

Purpose

The aim of this study was to investigate clinicopathologic differences between prostate cancer (PCa) detected at initial and repeat transrectal ultrasound-guided prostate biopsy in a large Korean cohort.

Materials and Methods

From 2000 through 2012, a total of 7,001 patients underwent transrectal ultrasound-guided prostate biopsy at 6 centers in Daegu and Gyeongbuk provinces. Of these 7,001 patients, the initial biopsy was positive for PCa in 2,118 patients. Repeat biopsy was performed in 374 of the 4,883 patients with an initial negative finding and a persistently elevated prostate-specific antigen (PSA) level, nodules or asymmetry by digital rectal examination (DRE), high-grade prostatic intraepithelial neoplasia, or atypical small acinar proliferation. Numbers of biopsy cores varied from 6 to 12 according to center and biopsy date.

Results

Cancer was diagnosed in 2,118 of the 7,001 patients (30.3%) at initial biopsy and in 86 of the 374 patients (23.0%) at repeat biopsy. The repeat biopsy rate was 5.3%. Mean PSA values were 68.7±289.5 ng/mL at initial biopsy and 18.0±55.4 ng/mL at repeat biopsy (p<0.001). The mean number of cancer-positive cores per biopsy was 5.5±3.5 for initial biopsy and 3.0±2.9 for repeat biopsy (p<0.001). Mean Gleason score was 7.5±1.4 at initial biopsy and 6.6±1.3 at repeat biopsy (p<0.001). For detected cancers, the low-stage rate was higher for repeat biopsy than for initial biopsy (p=0.001).

Conclusions

Cancers detected at repeat biopsy tend to have lower Gleason scores and stages than cancers detected at initial biopsy. The present study shows that repeat biopsy is needed in patients with a persistently high PSA or abnormal DRE findings.

Patterns of repeat prostate biopsy in contemporary clinical practice

PURPOSE

The objectives of this study were to 1) describe the patterns of repeat prostate biopsy in men with a previous negative biopsy and 2) identify predictors of prostate cancer diagnosis on repeat biopsy in these men.

MATERIALS AND METHODS

From a university faculty group practice we identified 1,837 men who underwent prostate biopsy between January 1, 1995 and January 1, 2010. Characteristics of repeat biopsy were examined, including the indication for biopsy, the number of repeat biopsies performed, the number of cores obtained and total prostate specific antigen before biopsy. Features of prostate cancer diagnosed on repeat biopsy were examined, including Gleason score, number of positive cores, percent of tumor and treatment choice. Multivariable logistic regression was done to identify prostate cancer predictors.

RESULTS

Initial biopsy was negative in 1,213 men. In 255 men a total of 798 repeat biopsies were performed. Of the 63 men diagnosed with prostate cancer Gleason score was 6 or less in 33 (52%), 7 in 22 (35%) and 8-9 in 8 (13%). When categorized by Epstein criteria, the rate of clinically insignificant cancer diagnosis decreased substantially by the third and fourth repeat biopsies. Repeat biopsy in men older than 70 years, biopsies including more than 20 cores and the fourth repeat biopsy were associated with an increased likelihood of prostate cancer diagnosis.

CONCLUSIONS

In men selected for multiple repeat biopsies clinically significant cancer is found at each sampling round. Given the continued likelihood of cancer detection even by the fifth biopsy, early consideration of saturation or image guided biopsy may be warranted in the repeat biopsy population.

Random biopsy: when, how many and where to take the cores?

PURPOSE

The optimal random prostate biopsy scheme (PBx) in the initial and repeated setting is still an issue of controversy. We performed an analysis of the recent literature about the prostate biopsy techniques.

METHODS

We performed a clinical and critical literature review by searching MEDLINE database from January 2005 up to January 2014. Electronic searches were limited to the English language, and the keywords prostate cancer, prostate biopsy, transrectal ultrasound, transperineal prostate biopsy were used.

RESULTS

Prostate biopsy strategy in initial setting. According to the literature and the major international guidelines, the recommended approach in initial setting is still the extended scheme (EPBx) (12 cores). However, there is now a growing evidence in the literature that (a) saturation PBx (>20 cores) (SPBx) might be indicated in patients with PSA <10 ng/ml or low PSA density or large prostate and (b) an individualized approach with more than 12 cores according to the clinical characteristics of the patients may optimize cancer detection in the single patient. Moreover, in the era of multi-parametric MRI (mpMRI), EPBx or SPBX may be substituted by mpMRI-targeted biopsies that have demonstrated superiority over systematic random biopsies for the detection of clinically significant disease and representation of disease burden, while deploying fewer cores. Prostate biopsy strategy in repeat setting. How and how many cores should be taken in the different scenarios in the repeated setting is still unclear. SPBx clearly improves cancer detection if clinical suspicion persists after previous biopsy with negative findings and is able to provide an accurate prediction of prostate tumour volume and grade. Nevertheless, international guidelines do not strongly recommended SPBx in all situations of repeated setting. In the active surveillance and in focal therapy protocols, the optimal schemes have to be defined.

CONCLUSIONS

The course of PBx has changed significantly from sextant biopsies to systematic and from extended to SPBx schemes. The issue about the number and location of the cores is still a matter of debate both in initial and in repeat setting. At present, EPBx is sufficient in most of the cases to provide adequate diagnosis and prostate cancer characterization in the initial setting, while SPBx seems to be necessary in repeat setting. The PBx schemes are evolving also because the scenario in which a PBx is necessary is changing. Random prostate PBx do not represent the future, while imaging target biopsy are becoming more popular.

Is there a role for anterior zone sampling as part of saturation trans-rectal ultrasound guided prostate biopsy?

Background

The prostatic anterior zone (AZ) is not targeted routinely by TRUS guided prostate biopsy (TRUS-Pbx). MRI is an accurate diagnostic tool for AZ tumors, but is often unavailable due to cost or system restrictions. We examined the diagnostic yield of office based AZ TRUS-Pbx.

Methods

127 men at risk for AZ tumors were studied: Patients with elevated PSA and previous extended negative TRUS-Pbx (group 1, n = 78) and actively surveyed low risk prostate cancer patients (group 2, n = 49). None of the participants had a previous AZ biopsy. Biopsy template included suspicious ultrasonic areas, 16 peripheral zone (PZ), 4 transitional zone (TZ) and 6 AZ cores. All biopsies were performed by a single urologist under local peri-prostatic anaesthetic, using the B-K Medical US System, an end-firing probe 4-12 MHZ and 18 ga/25 cm needle. All samples were reviewed by a single specialized uro-pathologist. Multivariate analysis was used to detect predictors for AZ tumors accounting for age, PSA, PSA density, prostate volume, BMI, and number of previous biopsies.

Results

Median PSA was 10.4 (group 1) and 7.3 (group 2). Age (63.9, 64.5), number of previous biopsies (1.5) and cores (17.8, 21.3) and prostate volume (56.4 cc, 51 cc) were similar for both groups. The overall diagnostic yield was 34.6% (group 1) and 85.7% (group 2). AZ cancers were detected in 21.8% (group 1) and 34.7% (group 2) but were rarely the only zone involved (1.3% and 4.1% respectively). Gleason ≥ 7 AZ cancers were often accompanied by equal grade PZ tumors. In multivariate analysis only prostate volume predicted for AZ tumors. Patients detected with AZ tumors had significantly smaller prostates (36.9 cc vs. 61.1 cc p < 0.001). Suspicious AZ ultrasonic findings were uncommon (6.3%).

Conclusions

TRUS-Pbx AZ sampling rarely improves the diagnostic yield of extended PZ sampling in patients with elevated PSA and previous negative biopsies. In low risk prostate cancer patients who are followed by active surveillance, AZ sampling changes risk stratification in 6% but larger studies are needed to define the role of AZ sampling in this population and its correlation with prostatectomy final pathological specimens.

Management of men with a suspicion of prostate cancer after negative initial prostate biopsy results

INTRODUCTION

For men with elevated prostate-specific antigen (PSA), appropriate management after negative prostate biopsy remains controversial. After determining PSA kinetics, subsequent follow-up was considered.

PATIENTS AND METHODS

A total of 115 cases with negative repeat biopsy were followed by evaluating PSA kinetics and ratio of percent free PSA (F/T) and by performing second repeat biopsy.

RESULTS

Eighteen cancer cases were diagnosed. Shorter PSA doubling times and faster velocities were found in cancer cases compared with cases without cancer. We observed a clear decrease in F/T among cancer cases.

CONCLUSIONS

To avoid unnecessary repeat biopsies, cases with a suspicion of cancer after negative biopsy can be divided into two groups: one that requires additional biopsies and one with an average change in PSA of <1 ng/ml/year and no change in F/T, which is recommended for surveillance as stable disease without biopsy over a specified time period.

Are more low-risk prostate cancers detected by repeated biopsy? A retrospective pilot study

PURPOSE

We hypothesized that there might be a higher incidence of low-risk prostate cancer (PCa) in men diagnosed at a repeated biopsy. Thus, we investigated differences in clinicopathological results of PCa after primary and repeated biopsy.

MATERIALS AND METHODS

We retrospectively reviewed patients diagnosed with PCa at a primary or repeated biopsy from January 2004 to April 2011. Patients were stratified into primary biopsy and repeated biopsy groups. We analyzed prostate-specific antigen, clinical stage, Gleason score (GS), positive core ratio, and low-risk group by using D'Amico classification. We also investigated GS upgrading and upstaging after radical prostatectomy (RP).

RESULTS

Among 448 primary and 37 repeated biopsy PCa patients, 82 (group 1) and 25 (group 2) underwent RP. The percentage of low-risk patients did not differ significantly between the groups. The positive biopsy core ratio was significantly lower in group 2 (p=0.009). The percentages of GS upgrading and upstaging were 42.7% and 47.6% in group 1, respectively (p=0.568), and 48.0% and 52.0% in group 2, respectively (p=0.901). In the analysis of low-risk patients, GS upgrading and upstaging were not significantly different between the groups (p=0.615 and p=0.959, respectively).

CONCLUSIONS

A lower positive core ratio may imply a small volume of PCa and possibly insignificant PCa in the repeated biopsy group. However, no significant differences were observed for the ratio of low-risk cancers, GS upgrading, or upstaging between the groups. Therefore, PCa diagnosed at a repeated biopsy is not an additional indication for active surveillance.

Detection rate of clinically insignificant prostate cancer increases with repeat prostate biopsies

To analyze if clinically insignificant prostate cancer (CIPC) is more frequently detected with repeat prostate biopsies, we retrospectively analyzed the records of 2146 men diagnosed with prostate cancer after one or more prostate biopsies. The patients were divided into five groups according to the number of prostate biopsies obtained, e.g. group 1 had one biopsy, group 2 had two biopsies and group 3 had three biopsies. Of the 2146 patients diagnosed with prostate cancer, 1956 (91.1%), 142 (6.6%), 38 (1.8%), 9 (0.4%) and 1 (0.1%) men were in groups 1, 2, 3, 4 and 5, respectively. Groups 4 and 5 were excluded because of the small sample sizes. The remaining three groups (groups 1, 2 and 3) were statistically analyzed. There were no differences in age or prostate-specific antigen level among the three groups. CIPC was detected in 201 (10.3%), 28 (19.7%) and 9 (23.7%) patients in groups 1, 2 and 3, respectively (P<0.001). A multivariate analysis showed that the number of biopsies was an independent predictor to detect CIPC (OR=2.688 for group 2; OR=4.723 for group 3). In conclusion, patients undergoing multiple prostate biopsies are more likely to be diagnosed with CIPC than those who only undergo one biopsy. However, the risk still exists that the patient could have clinically significant prostate cancer. Therefore, when counseling patients with regard to serial repeat biopsies, the possibility of prostate cancer overdiagnosis and overtreatment must be balanced with the continued risk of clinically significant disease.

Optimal prostate biopsy regimen

The prostate-specific antigen (PSA) era has increased the rates of prostate cancer detection and treatment, while reducing the risk of death from prostate cancer in the US. Image-guided prostate biopsy techniques have led to stage migration and the detection and treatment of lower risk prostate cancers. Improved techniques with laterally directed biopsy, office-based saturation biopsy, and transperineal biopsy under anesthesia have increased the detection rates of smaller volume tumors. Improved detection of ever-smaller tumors assists the clinician in determining what treatment is most appropriate for the patient, including the use of active surveillance and focal therapy. Furthermore, the detection of small volume, high grade cancers may widen the latency interval in which a clinically significant tumor may be detectable and curable.

Differences in Postoperative Pathological Outcomes between Prostate Cancers Diagnosed at Initial and Repeat Biopsy

Purpose

We evaluated the differences in pathological outcomes between prostate cancers (PCas) diagnosed at initial and repeat biopsy.

Materials and Methods

We retrospectively reviewed the medical records of 287 patients who underwent radical retropubic prostatectomy from 2005 to 2010. We investigated preoperative factors, such as age, serum prostate-specific antigen (PSA), prostate volume (PV), digital rectal examination (DRE) results, biopsy schema, clinical stage, and number of prior biopsies, and postoperative pathological outcomes, including specimen volume, percent tumor volume, Gleason score (GS), tumor bilaterality, pathological stage, positive surgical margin (PSM), lymphovascular invasion (LVI), and perineural invasion (PNI). Patients were then classified into two groups by the number of prior biopsies (initial biopsy vs. repeat biopsy). We compared preoperative factors and postoperative pathological outcomes between the two groups.

Results

Of the 287 patients, 246 (85.7%) were diagnosed with cancer at the initial biopsy and 41 (14.3%) at the repeat biopsy. The repeat biopsy group was older (p=0.048), had a larger PV (p=0.009), had a significantly different biopsy schema (p<0.001), and had a lower (<10%) percentage tumor volume (p=0.016). In the multivariate analysis (after adjustment for biopsy schema, age, serum PSA, PV, and DRE), repeat biopsy was not an independent predictor of GS, tumor bilaterality, pathological stage, PSM, LVI, or PNI (p=0.212, 0.456, 0.459, 0.917, 0.991 and 0.827, respectively), but repeat biopsy could predict lower percentage tumor volume (p=0.037).

Conclusions

The pathological outcomes of PCas detected at repeat biopsy were not significantly different from those of PCas detected at initial biopsy except for a lower (<10%) percentage tumor volume.

Are repeat prostate biopsies safe? A cohort analysis from the SEARCH database

PURPOSE

Patients question whether multiple biopsy sessions cause worse prostate cancer outcomes. Therefore, we investigated whether there is an association between the number of prior biopsy sessions and biochemical recurrence after radical prostatectomy.

MATERIALS AND METHODS

Men in the SEARCH (Shared Equal Access Regional Cancer Hospital) database who underwent radical prostatectomy between 1988 and 2010 after a known number of prior biopsies were included in the analysis. Number of biopsy sessions (range 1 to 8) was examined as a continuous and categorical (1, 2 and 3 to 8) variable. Biochemical recurrence was defined as a prostate specific antigen greater than 0.2 ng/ml, 2 values at 0.2 ng/ml or secondary treatment for an increased prostate specific antigen. The association between number of prior biopsy sessions and biochemical recurrence was analyzed using the Cox proportional hazards model. Kaplan-Meier estimates of freedom from biochemical recurrence were compared among the groups.

RESULTS

Of the 2,739 men in the SEARCH database who met the inclusion criteria 2,251 (82%) had only 1 biopsy, 365(13%) had 2 biopsies and 123 (5%) had 3 or more biopsies. More biopsy sessions were associated with higher prostate specific antigen (p<0.001), greater prostate weight (p<0.001), lower biopsy Gleason sum (p=0.01) and more organ confined (pT2) disease (p=0.017). The Cox proportional hazards model demonstrated no association between number of biopsy sessions as a continuous or categorical variable and biochemical recurrence. Kaplan-Meier estimates of freedom from biochemical recurrence were similar across biopsy groups (log rank p=0.211).

CONCLUSIONS

Multiple biopsy sessions are not associated with an increased risk of biochemical recurrence in men undergoing radical prostatectomy. Multiple biopsy sessions appear to select for a low risk cohort.

When serial prostate biopsy is recommended: most cancers detected are clinically insignificant

Study Type - Disagnostic (exploratory cohort) Level of Evidence 2b. What's known on the subject? and What does the study add? Many patients undergo serial biopsy with a low rate of detection of prostate cancer, and the rate of detection declines as more biopsies are pursued. Furthermore, the clinical significance of detected cancer appears to decline as well. It is important to follow all possible methods to detect cancer; however, there should be a parallel consideration for the clinical value for detection of these tumours with low malignant potential. The present study investigated in detail the total rate of cancer detection in serial biopsy and how many of these were deemed clinically insignificant. Moreover, it addressed the impact of detecting premalignant lesions on further detection of cancer in serial biopsy.

OBJECTIVE

Many patients pursue serial prostate biopsies after two consecutive negative biopsy sessions. The objective of this study is to determine the indications of serial prostate biopsy and to compare outcomes, including the risk of detecting clinically insignificant cancer using different biopsy protocols in this highly selected population.

PATIENTS AND METHODS

• Most cases of prostate cancer are detected on initial or one repeat biopsy, but persistent suspicion of prostate cancer occasionally leads to serial biopsy, which we define as more than two biopsy sessions. We recently showed that transrectal saturation biopsy (sPBx) significantly increases cancer detection when compared with extended schemes (ePBx) in the initial repeat biopsy (second overall biopsy) population, and that most cases identified are clinically significant. • In the past decade, 479 men underwent 749 repeat prostate biopsies after two prior negative biopsy sessions. • The ePBx group included 347 biopsies with 10-14 cores. • The sPBx group included 402 biopsies with >20 cores. • We analysed overall cancer detection and risk of detecting clinically significant vs insignificant tumours.

RESULTS

Prostate cancer was detected in 15.9% of 749 serial biopsies, representing a cumulative prostate cancer detection rate of 24.8% (119/479 patients). • The sPBx group had a significantly higher detection rate per biopsy session (18.6% vs 12.7%, P= 0.026). • Nevertheless, most positive biopsies 75/119 (63%) revealed clinically insignificant cancer, including 74.6% of cancers detected by sPBx.

CONCLUSION

In men with two prior negative prostate biopsies, prostate cancer detection remains low regardless of clinical indication or transrectal biopsy protocol; most cancers identified are clinically insignificant, suggesting the threshold to repeat biopsy after more than one negative session should be very high.

Type of transrectal ultrasonography probe influences prostate cancer detection rates on repeat prostate biopsy

It is known that the end-fire probe detects more prostate cancer on initial prostate biopsy, but there is no literature looking at the influence of type of probe on repeat biopsy. Given that the literature on the influence of ultrasonography probe on repeat prostate biopsy is non-existent, the present study adds information which may help urologists improve their chances of detecting prostate cancer on prostate biopsy. Determining which type of probe to use on a prostate biopsy is a simple external factor that may help improve patient management.

OBJECTIVE

To determine if the type of transrectal ultrasonography (TRUS) probe used during repeat prostate biopsy influences prostate cancer detection rates.

PATIENTS AND METHODS

We conducted a retrospective chart review of 680 men undergoing repeat prostate biopsy at our institution between 2000 and 2010. Patient mean (range) age was 64.2 (39-95) years. The median (range) prostate-specific antigen (PSA) level was 5.5 (0.37-33.8) ng/mL and median (range) free PSA was 17 (5-45) %. Patient age, PSA, prostate volume, number of biopsy cores, time interval between initial and repeat biopsy, digital rectal examination and pathological findings were all included in a multivariate logistic regression analysis.

RESULTS

The use of an end-fire probe on repeat biopsy significantly increased prostate cancer detection (odds ratio [OR] 1.59, 95% confidence interval [CI]: 1.03-2.46). The time interval between 1(st) and 2(nd) biopsy was also significant (OR 1.46, 95% CI: 1.11-1.09). On univariate analysis, white race (OR 0.66, 95% CI: 0.44-0.99), increasing prostate volume (OR 0.70, 95% CI: 0.55-0.89), and higher free PSA (OR 0.54, 95% CI: 0.34-0.84) were associated with a decreased risk of cancer. When evaluating the different permutations of using an end-fire or side-fire probe on initial or repeat biopsy, there was no difference in prostate cancer detection regardless of order of use of an end-fire or side-fire probe.

CONCLUSIONS

An end-fire probe is associated with improved prostate cancer detection rates on both initial and repeat biopsy. The order of probe use does not appear to matter.

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.

Statin use and risk of prostate cancer in a population of men who underwent biopsy

PURPOSE

We determined the association between statin use and prostate cancer in men who underwent prostate biopsy.

MATERIALS AND METHODS

We performed a retrospective cohort study of men who underwent prostate biopsy from 2000 to 2007 at Cleveland Clinic. Statin use was determined using outpatient pharmacy records, and clinical and pathological outcomes were obtained. Multivariate logistic regression analysis to determine the effects of statins (and duration of use) was performed after adjusting for age, body mass index, African-American race, number of cores taken and prostate volume.

RESULTS

We analyzed data from 4,204 patients, and we identified 3,182 (75.7%) not on statins and 1,022 on statins. Men diagnosed with prostate cancer on statins compared to those not taking statins were less likely to have digital rectal examination positivity (5.3% vs 8.9%, OR 0.7, p <0.01), Gleason score 7 or greater prostate cancer (61.4% vs 72.4%, OR 0.78, p = 0.02) and high volume prostate cancer (27.2 vs 31.4, p <0.01). Moreover statin users had lower prostate specific antigen compared to nonstatin users (5.13 vs 5.98, p = 0.03). Multivariate analysis adjusted risk ratios for prostate cancer diagnosis, high grade prostate cancer (Gleason score 7 or greater) and 3 or more cores positive in statin users were 0.92 (95% CI 0.85-0.98), 0.76 (95% CI 0.67-0.85) and 0.86 (95% CI 0.75-0.97) and only high grade prostate cancer persisted with length of use.

CONCLUSIONS

Statin use was associated with a decreased risk of prostate cancer, less frequent high grade prostate cancer and lower volume of prostate cancer, suggesting that statin use has a protective effect against prostate cancer.

Repeat prostate biopsy and the incremental risk of clinically insignificant prostate cancer

OBJECTIVES

To determine the incremental risk of diagnosis of clinically insignificant prostate cancer with serial prostate biopsies.

METHODS

We reviewed our institutional radical prostatectomy (RP) database comprising 2411 consecutive patients undergoing RP. We then stratified patients by the prostate biopsy on which their cancer was diagnosed and correlated biopsy number with the risk of clinically insignificant disease and adverse pathology at radical prostatectomy.

RESULTS

A total of 1867 (77.4%), 281 (11.9%), and 175 (7.3%) patients underwent 1, 2, and 3 or more prostate biopsies, respectively, before RP. Increasing number of prostate biopsies was associated with increasing prostate volume (P <.01), prostate-specific antigen (P <.01), associated prostate intraepithelial neoplasia (P <.01), and increased likelihood of clinical Gleason 6 or less disease (P <.01). On pathologic analysis, increasing number of prostate biopsies was associated with increased risk of low-volume (P <.01), organ-confined (P <.01) disease. The risk of clinically insignificant disease was found to be 31.1%, 43.8%, and 46.8% in those undergoing 1, 2, and 3+ prostate biopsies, respectively. Conversely, the risk of adverse pathology was found to be 64.6%, 53.0%, and 52.0% in those undergoing 1, 2, and 3+ prostate biopsies, respectively.

CONCLUSIONS

Patients undergoing multiple prostate biopsies before RP are more likely to harbor clinically insignificant prostate cancer than those who only undergo 1 biopsy before resection. Nonetheless, the risk of adverse pathology in patients undergoing serial biopsies remains significant. The increased risk of prostate cancer overdiagnosis and overtreatment must be balanced with the continued risk of clinically significant disease when counseling patients regarding serial biopsies.

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 role of PCA3 testing in patients with a raised prostate-specific antigen level after Greenlight photoselective vaporization of the prostate

BACKGROUND AND PURPOSE

Greenlight(®) photoselective vaporization of the prostate (PVP) is an effective method for treating men with lower urinary tract symptoms. A rise in prostate specific antigen (PSA) levels, however, may be noticed in some patients during follow-up. The aim of this study was to determine whether the prostate cancer gene 3 (PCA3) urinary test would help identify patients who were in need of a prostate biopsy.

PATIENTS AND METHODS

The PSA of all patients undergoing PVP were analyzed. Patients with an elevated (above reference range) or rising PSA level (defined as > 0.75 ng/mL/year if the PSA was between 4.1 and 10 or a doubling time of less than 2 years) were offered a transrectal ultrasonography (TRUS) guided prostate biopsy. Before the biopsy procedure, all patients had a PCA3 test. The relationships between PSA, PCA3, and TRUS prostate biopsy findings were analyzed to determine sensitivity and specificity for the PCA3 test in this setting.

RESULTS

50 patients were identified. The mean age was 69.97 (range 57-83) years. The mean PSA level was 10.1 ng/mL (range 3.03-44.2 ng/mL). Six patients were found to have prostate cancer. Of those, five patients had a positive PCA3 test. One patient had a negative PCA3 test but positive biopsy findings. This gives a sensitivity of 83.3%, and a positive predictive value of 21.7%. The negative predictive value was 96%.

CONCLUSION

The results suggest that a negative PCA3 test in our group of patients is a good predictor of negative biopsy results. The low positive predictive value may be an artefact of the group size. This will need further investigation and greater patient numbers to determine.

Effect of the number of biopsy cores on prostate cancer detection and staging

Digital rectal examination, serum concentration of prostate cancer-specific antigen and transrectal ultrasound-guided biopsies are currently the main diagnostic tools to detect evidence of prostate cancer. Different prostatic biopsy strategies have been proposed in order to achieve an optimal prostate cancer detection rate and an accurate characterization of prostate cancer stage and grade. We examined the role of the number of biopsy cores on prostate cancer detection rates at initial and repeat biopsies. Moreover, we examined the relationship between the number of biopsy cores and the detection of insignificant prostate cancer. Finally, we reviewed the ability of biopsy cores in predicting prostate cancer stage and grade at radical prostatectomy. We relied on a PubMed systematic review of the contemporary English language literature using the terms ‘prostate cancer’, ‘diagnosis’, ‘transrectal ultrasound’ and ‘prostate biopsy’.

Small Volume (<0.5 cc) Prostate Cancer: Characteristics and Clinical Implications

Introduction

It is not well known how many Small Volume Prostate Cancers (SVPC) may host high grade (Gleason pattern 4/5) or have extraprostatic extension in particular in the national setting. Features of SVPC are very interesting since they raise controversies in diagnosis and have important clinical implications in treatment strategies. The diagnosis may be difficult and the treatment ranges from active surveillance to radical surgery. AIM. We evaluate clinical and pathological features of SVPC in surgical specimens of patients who underwent biopsy and radical prostatectomy.

Methods

We analysed a consecutive series of 849 radical prostatectomies performed between 2005 and 2008. Inclusion criteria were: biopsy specimen available, pathological tumor volume analysis according to standard criteria, whole-mount section 3 mm step analysis according to Stanford protocol, clinical parameters (PSA, DRE, number of core biopsy taken). Exclusion criteria: any hormonal manipulation before surgery and cT1A/B stage. Data were analysed using SPSS for statistical comparison.

Results

238 patients were evaluated. SVPC<0.5 cc was observed in 58 (24.3%). Overall in 17/58 (29.3%) a clinical/pathological relevant disease was observed. In 16/58 (27.5%) pathological Gleason Score (GS) was 7–8, in 5/58 (9%) pathological stage was T3. The number of tumor foci was >1 in 78.3%, tumor-involving in both lobes in 55%. Unifocal disease was observed in 22%. Clinically relevant disease is significantly associated with total cancer volume (0.20 versus 0.31, p 0.007), but not to tumor foci (2.5 versus 2.0). PSA, age, no. of positive cores, DRE were not predictive of clinical relevant disease. Six of 17 (35%) cases with SVPC - who were in the low risk category (PSA <10, biopsy Gleason score <7 and negative DRE), had clinical relevant disease.

Conclusion

SVPC are clinically relevant in 29.3% since they have a Gleason pattern 4 (27.5%) or have only pathological T3 (9%). Early diagnosis techniques and treatments have to consider that SVPC prostate cancer may contain high risk disease in 1/4 of cases. Clinical parameters are not useful to accurately detect high risk SVPC.

Performance of transperineal template-guided mapping biopsy in detecting prostate cancer in the initial and repeat biopsy setting

Transrectal ultrasound (TRUS) biopsy can miss 20-30% of clinically significant cancers. We evaluate an alternative approach-transperineal template-guided mapping biopsy (TTMB) in the initial and repeat biopsy setting. From January 2005 through September 2008, 373 consecutive men underwent TTMB (294 men with > or =1 prior negative biopsy and 79 men as the initial biopsy). The location of each positive biopsy core, number of positive cores, and percent involvement of each core was recorded. Cancer detection rate for the initial biopsy was 75.9%. For men with 1, 2, and > or =3 prior negative biopsies detection rates were 55.5%, 41.7%, and 34.4%, respectively. In all, 55.5% of the cancers identified were Gleason > or =7. The majority of the cancers were multifocal. There was no significant change in the number of positive cores or Gleason score as the number of prior biopsies increased. The anterior and apical aspects of the prostate were among the most common cancer locations. TTMB provides a high rate of cancer detection as initial and repeat biopsy. TTMB was particularly effective at diagnosing anterior and apical cancer. TTMB may have particular application for men considering active surveillance, with prior negative TRUS biopsies, and those considering subtotal gland or other minimally invasive treatments.

Prostate cancer: diagnosis and staging

Prostate cancer represents an increasing health burden. The past 20 years, with the introduction of prostate-specific antigen (PSA), has seen prostate cancer move increasingly from a condition that presented with locally advanced disease or metastases to one that is found upon screening. More is also known about the pathology of pre-malignant lesions. Diagnosis relies on trans-rectal ultrasound (TRUS) to obtain biopsies from throughout the prostate, but TRUS is not useful for staging. Imaging for staging, such as magnetic resonance imaging or computed tomography, still has a low accuracy compared with pathological specimens. Current techniques are also inaccurate in identifying lymph node and bony metastases. Nomograms have been developed from the PSA, Gleason score and clinical grading to help quantify the risk of extra-capsular extension in radical prostatectomy specimens. Improved clinical staging modalities are required for more reliable prediction of pathological stage and for monitoring of response to treatments.