Is extended and saturation biopsy necessary?

Identifying Risk Factors for MRI-Invisible Prostate Cancer in Patients Undergoing Transperineal Saturation Biopsy

Purpose

Prostatic multi-parametric magnetic resonance imaging (mpMRI) has markedly improved the assessment of men with suspected prostate cancer (PCa). Nevertheless, as mpMRI exhibits a high negative predictive value, a negative MRI may represent a diagnostic dilemma. The aim of this study was to evaluate the incidence of positive transperineal saturation biopsy in men who have negative mpMRI and to analyse the factors associated with positive biopsy in this scenario.

Patients and Methods

A retrospective study of men with normal mpMRI and suspicion of PCa who underwent saturation biopsy (≥20 cores) was carried out. A total of 580 patients underwent transperineal MRI/transrectal ultrasound fusion targeted biopsies or saturation prostate biopsies from January 2017 to September 2020. Of them, 73 had a pre-biopsy negative mpMRI (with Prostate Imaging – Reporting and Data System, PI-RADS, ≤2) and were included in this study. Demographics, clinical characteristics, data regarding biopsy results and potential predictive factors of positive saturation biopsy were collected. Univariate and multivariate logistic regression analyses were used to identify independent risk factors for MRI-invisible PCa.

Results

The detection rate of PCa with saturation biopsy in patients with negative MRI was 34/73 (46.58%). Out of 34 MRI-invisible prostate cancers detected, 12 (35.29%) were clinically significant PCa (csPCa) forms. Regarding factors of positive biopsy, in univariate analysis, the use of 5-alpha reductase inhibitors and free:total prostate-specific antigen (PSA) ratio were associated with the result of the saturation biopsy. In multivariate analysis, only an unfavourable free:total PSA ratio remained a risk factor (OR 11.03, CI95% 1.93–63.15, p=0.01). Furthermore, multivariate logistic analysis demonstrated that prostate volume >50mL significantly predicts the absence of csPCa on saturation biopsy (OR 0.11, 95% CI 0.01–0.94, p=0.04).

Conclusion

A free:total PSA ratio <20% is a risk factor for MRI-invisible PCa. Saturation biopsy could be considered in patients with suspected PCa, despite having a negative MRI.

Cost-effectiveness of MRI targeted biopsy strategies for diagnosing prostate cancer in Singapore

BACKGROUND

To evaluate the cost-effectiveness of six diagnostic strategies involving magnetic resonance imaging (MRI) targeted biopsy for diagnosing prostate cancer in initial and repeat biopsy settings from the Singapore healthcare system perspective.

METHODS

A combined decision tree and Markov model was developed. The starting model population was men with mean age of 65 years referred for a first prostate biopsy due to clinical suspicion of prostate cancer. The six diagnostic strategies were selected for their relevance to local clinical practice. They comprised MRI targeted biopsy following a positive pre-biopsy multiparametric MRI (mpMRI) [Prostate Imaging - Reporting and Data System (PI-RADS) score ≥ 3], systematic biopsy, or saturation biopsy employed in different testing combinations and sequences. Deterministic base case analyses with sensitivity analyses were performed using costs from the healthcare system perspective and quality-adjusted life years (QALY) gained as the outcome measure to yield incremental cost-effectiveness ratios (ICERs).

RESULTS

Deterministic base case analyses showed that Strategy 1 (MRI targeted biopsy alone), Strategy 2 (MRI targeted biopsy ➔ systematic biopsy), and Strategy 4 (MRI targeted biopsy ➔ systematic biopsy ➔ saturation biopsy) were cost-effective options at a willingness-to-pay (WTP) threshold of US$20,000, with ICERs ranging from US$18,975 to US$19,458. Strategies involving MRI targeted biopsy in the repeat biopsy setting were dominated. Sensitivity analyses found the ICERs were affected mostly by changes to the annual discounting rate and prevalence of prostate cancer in men referred for first biopsy, ranging between US$15,755 to US$23,022. Probabilistic sensitivity analyses confirmed Strategy 1 to be the least costly, and Strategies 2 and 4 being the preferred strategies when WTP thresholds were US$20,000 and US$30,000, respectively.

LIMITATIONS AND CONCLUSIONS

This study found MRI targeted biopsy to be cost-effective in diagnosing prostate cancer in the biopsy-naïve setting in Singapore.

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.

Impact of extended prostate biopsy including apical anterior region for cancer detection and prediction of surgical margin status for radical prostatectomy

Objectives

We investigated diagnostic yield of initial biopsy and repeated biopsy including apical cores.

Methods

We investigated 573 consecutive men with PSA of ≤20 ng/ml who underwent prostate biopsy between 2004 and 2013. The initial 14-core biopsy consisted of the sextant type, lateral sites at the base and middle, lateral apices (la) at anterior horn sites, and apical anterior sites (aa). The repeated 18-core biopsy consisted of the initial 14-core biopsy with four transition zone (TZ) sites at the base (tzb) and middle (tzm).

Results

Prostate cancer was diagnosed in 178 (38.9%) of 458 men with the initial 14-core biopsy, and 44 (38.3%) of 115 men with the repeated 18-core biopsy. In the initial biopsy setting, the unique cancer detection rate was high in apical sites (apex, la, and aa: 6.2%, 6.2% and 5.1%, respectively). In the repeated setting, it was high in the TZ site in addition to the apical site (apex, la, aa, tzm, and tzb: 6.8%, 6.8%, 11.4%, 9.1% and 11.4%, respectively). The positive SM rate at the apex was higher in patients whose cancer was detected only in sites other than the sextant region than for those in the sextant region (36.4% vs. 14.8%, P = 0.037).

Conclusions

The initial 14-core and the repeated 18-core biopsy scheme including apical anterior cores are feasible for prostate cancer detection. We propose that apical biopsy cores can be used to predict not only the existence of cancer but also surgical margin status at the apex.

Prostate Biopsy-related Infection: A Systematic Review of Risk Factors, Prevention Strategies, and Management Approaches

A systematic review to identify risk factors for prostate biopsy-related infection, preventative strategies, and optimal management of infectious complications was conducted. Significant risk factors for postbiopsy infection include urogenital infection, antibiotic use, international travel, hospital exposure, bacteriuria, previous transrectal biopsy, and resistance of fecal flora to antibiotic prophylaxis (especially fluoroquinolones). Patients at risk may benefit from an adjusted biopsy protocol comprising transrectal biopsy under targeted prophylaxis, and/or the use of rectal disinfection techniques or using a transperineal approach. Management of biopsy-related infection should be based on individual risk and local resistance profiles with input from multiple specialties.

A combination of Korean mistletoe extract and resistance exercise retarded the decline in muscle mass and strength in the elderly: A randomized controlled trial

Given the increased concerns about the degenerative decline in the physical performance of the elderly, there is a need for developing effective strategies to suppress the age-related loss of skeletal muscle mass and functional capacity through a lifestyle intervention. This randomized controlled trial examined whether a combination of Korean mistletoe extract (KME) supplement and exercise affected muscle mass, muscle function, and targeted molecular expressions. Sixty-seven subjects aged 55-75years were assigned to placebo, low-dose (1g/d), or high-dose (2g/d) of KME for 12weeks. The body composition was significantly changed in the high-dose group during the intervention period as determined by skeletal muscle mass (P=0.040), fat free mass (P=0.042), soft lean mass (P=0.023), skeletal muscle index (P=0.041), fat-free mass index (P=0.030), percent body fat (P=0.044), and fat mass to lean mass ratio (P=0.030). Knee strength was measured by Cybex, demonstrating a significant effect in the KME groups compared to the placebo group (P=0.026 for peak torque and P=0.057 for set total work), which was more pronounced after adjusting for age, gender, protein, and energy intake (P=0.009 for peak torque and P=0.033 for set total work). The dynamic balance ability was remarkably improved in the high-dose group over a 12-week period as determined by Timed "Up and Go" (P=0.005 for fast walk test and P=0.024 for ordinary walk test). Consistent with these results, RT-PCR, multiplex analyses, and immunocytofluorescence staining revealed that a high-dose KME supplementation was effective for suppressing intracellular pathways related to muscle protein degradation, but stimulating those related to myogenesis. In particular, significant differences were found in atrogin-1 mRNA (P=0.002 at a single administration and P=0.001 at a 12-week administration), myogenin mRNA (P<0.0001 at a single administration and P=0.040 at a 12-week administration), and insulin growth factor 1 receptor phosphorylation (P=0.002 at a 12-week administration). These results suggest that KME supplementation together with resistance exercise may be useful in suppressing the age-related loss of muscle mass and strength in the elderly.

Developing a model for forecasting Gleason score ≥7 in potential prostate cancer patients to reduce unnecessary prostate biopsies

PURPOSE

The diagnosis of Gleason score (GS) ≥7 with distinction from GS < 7 remains a difficult problem instructing clinical decisions. Moreover, the present wide application of prostate biopsy to increase prostate cancer detection rate might cause unnecessary and excessive examination or treatment. Therefore, a risk assessment model for forecasting GS ≥ 7 in potential prostate cancer patients was established to reduce unnecessary prostate biopsies.

METHODS

Patients (n = 981; September 2009 to January 2013) who underwent trans-rectal ultrasound (TRUS)-guided core prostate biopsy were retrospectively evaluated in the first stage of the study. Age, prostate-specific antigen (PSA), free PSA (fPSA), the free/total PSA ratio (f/t), prostate volume (PV), PSA density (PSAD), digital rectal examination (DRE) findings (texture, nodules) and B-ultrasound detection results (normal or abnormal, presence of hypoechoic mass or microcalcification) were considered as potential predictive factors. After multiple logistic regression analysis, independent variables used to build a nomogram were selected using a backward elimination selection procedure. Then, a model to forecast GS ≥ 7 was designed for potential prostate cancer patients. In the second stage of the study, 410 cases (January 2013 to March 2015) were subsequently evaluated using our model for prostate biopsies, and the outcomes of biopsies were compared between the two stages.

RESULTS

PSA, DRE texture, DRE nodules and B-ultrasound results were finally brought into our nomogram; a obviously greater area under the receiver operating characteristic (ROC) curve was obtained for the model than utilizing PSA, fPSA or PSAD alone (0.831 vs. 0.803, 0.770, 0.780 separately). We thereafter sought the best cutoff value in the ROC curve at 0.87, which provided sensitivity as high as 90%. Meanwhile, the specificity was 45.8%, which was much higher than the specificity of PSA, fPSA and PSAD at the same sensitivity level (37.7, 24.6 and 35.2%, respectively). In the first stage, the detection rate of GS ≥ 7 in the high-risk group was significantly higher than in the low-risk group (80.3 vs. 35.0%, p < 0.001). Furthermore, in the second stage, with the application of the new model associated with our former models, the rate of GS ≥ 7 was improved from 71.0 (697/981) to 79.2% (267/337) (p = 0.003).

CONCLUSIONS

The model for forecasting GS ≥ 7 is effective, which could reduce unnecessary prostate biopsies without delaying patients' diagnoses and treatments.

Selective Low-Dose Spinal Anesthesia for Transrectal Prostate Biopsy: A Prospective and Randomized Study

PURPOSE

To evaluate the use of spinal anesthesia by reducing anesthetic agent dose to provide better analgesia with minimal side effects without sacrificing the outpatient setting for prostate biopsy. In this study, efficacy and tolerability of selective low-dose spinal anesthesia versus intrarectal local anesthesia (IRLA) plus periprostatic nerve blockade (PPNB) were compared.

METHODS

Between September 2012 and April 2013, 100 patients, aged 40 to 80 years, prostate-specific antigen (PSA) ≥4 ng/mL, abnormal digital rectal examinations, and enrolled for biopsy were included in the present study. Ensuring double blindness, pain was assessed using the visual analog scale (VAS). Anal sphincter relaxation, patient satisfaction with the anesthesia technique, and motor response were evaluated.

RESULTS

Differences between the two groups, considering age, American Society of Anesthesiologist score, total PSA, prostate volume, anesthesia duration, and cancer presence, were not statistically significant. Pain experienced during probe insertion, biopsy, and 30 minutes after biopsy was significantly lower in the low-dose spinal anesthesia group (P < 0.0001). Anal sphincter relaxation degree was significantly higher in the spinal group (P < 0.001). Patient procedure-related overall satisfaction level was significantly higher in the spinal anesthesia group (P < 0.001). In the spinal anesthesia group, no motor blockade was observed. Between the two groups, no statistically significant difference was seen with regard to complications (P > 0.05).

CONCLUSION

Selective low-dose spinal anesthesia provides better pain relief than PPNB plus IRLA without sacrificing the day case setting in ambulatory practice. It is also associated with high patient satisfaction and willingness for a repeated biopsy without differences in procedure duration, tolerance, and complications.

3-Tesla magnetic resonance imaging improves the prostate cancer detection rate in transrectral ultrasound-guided biopsy

The detection rate of prostate cancer (PCa) using traditional biopsy guided by transrectal ultrasound (TRUS) is not satisfactory. The aim of this study was to determine the utility of 3-Tesla (3-T) magnetic resonance imaging (MRI) prior to TRUS-guided prostate biopsy and to investigate which subgroup of patients had the most evident improvement in PCa detection rate. A total of 420 patients underwent 3-T MRI examination prior to the first prostate biopsy and the positions of suspicious areas were recorded respectively. TRUS-guided biopsy regimes included systematic 12-core biopsy and targeted biopsy identified by MRI. Patients were divided into subgroups according to their serum prostate-specific antigen (PSA) levels, PSA density (PSAD), prostate volume, TRUS findings and digital rectal examination (DRE) findings. The ability of MRI to improve the cancer detection rate was evaluated. The biopsy positive rate of PCa was 41.2% (173/420), and 41 of the 173 (23.7%) patients were detected only by targeted biopsy in the MRI-suspicious area. Compared with the systematic biopsy, the positive rate was significantly improved by the additional targeted biopsy (P=0.0033). The highest improvement of detection rate was observed in patients with a PSA level of 4–10 ng/ml, PSAD of 0.12–0.20 ng/ml², prostate volume >50 ml, negative TRUS findings and negative DRE findings (P<0.05). Therefore, it is considered that 3-T MRI examination could improve the PCa detection rate on first biopsy, particularly in patients with a PSA level of 4–10 ng/ml, PSAD of 0.12–0.20 ng/ml², prostate volume of >50 ml, negative TRUS findings and negative DRE findings.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The value of diffusion-weighted imaging in the detection of prostate cancer: a meta-analysis

Objectives

To evaluate the diagnostic performance of diffusion-weighted imaging (DWI) as a single non-invasive method in detecting prostate cancer (PCa) and to deduce its clinical utility.

Methods

A systematic literature search was performed to identify relevant original studies. Quality of included studies was assessed by QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies). Data were extracted to calculate sensitivity and specificity as well as running the test of heterogeneity and threshold effect. The summary receiver operating characteristic (SROC) curve was drawn and area under SROC curve (AUC) served as a determination of the diagnostic performance of DWI for the detection of PCa.

Results

A total of 21 studies were included, with 27 subsets of data available for analysis. The pooled sensitivity and specificity with corresponding 95 % confidence interval (CI) were 0.62 (95 % CI 0.61–0.64) and 0.90 (95 % CI 0.89–0.90), respectively. Pooled positive likelihood ratio and negative likelihood ratio were 5.83 (95 % CI 4.61–7.37) and 0.30 (95 % CI 0.23–0.39), respectively. The AUC was 0.8991. Significant heterogeneity was observed. There was no notable publication bias.

Conclusions

DWI is an informative MRI modality in detecting PCa and shows moderately high diagnostic accuracy. General clinical application was limited because of the absence of standardized DW-MRI techniques.

Key points

• DWI provides incremental information for the detection and evaluation of PCa

• DWI has moderately high diagnostic accuracy in detecting PCa

• Patient condition, imaging protocols and study design positively influence diagnostic performance

• General clinical application requires optimization of image acquisition and interpretation

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.

Incremental detection rate of prostate cancer by real-time elastography targeted biopsies in combination with a conventional 10-core biopsy in 1024 consecutive patients

OBJECTIVE

To quantify the incremental detection rate (DR) of a targeted biopsy in addition to a randomized 10-core biopsy.

PATIENTS AND METHODS

This retrospective study analysed 1024 patients who consecutively underwent a four-core real-time elastography (RTE) targeted biopsies in addition to a randomized 10-core transrectal ultrasonography (TRUS)-guided biopsy in a primary or rebiopsy setting. The overall DR, the DR of a 10-core randomized, RTE targeted biopsy and the incremental DR were calculated.

RESULTS

Overall, randomized and RTE targeted biopsy DRs (for the combination, the 10-core and the four-core RTE biopsy scheme) were 46.2% (n = 473), 39.1% (n = 400) and 29.0% (n = 297), respectively. Four-core RTE targeted biopsies detected an additional 73 patients not detected by the 10-core randomized biopsies (increase in the overall DR of 7.1%). This represented a relative increase in DR of 18.3%. The incremental DR was better in rebiopsy patients (24.8%) than in patients having their first biopsy (14.7%). Within all patients diagnosed by RTE targeted biopsy only, 34 patients harboured significant Gleason 4 or 5 prostate cancer (PCa), diagnosed by four-core RTE biopsy only. Moreover, PCa with a Gleason grade of 4 or 5 was detected by four-core RTE biopsies in 30 patients, who showed low-grade PCa ≤ Gleason 3 only in the systematic 10-core biopsy.

CONCLUSIONS

Real-time elastography targeted biopsy seems to be an appropriate method for increasing the DR of PCa. Nevertheless, RTE targeted biopsies missed a high proportion of patients with PCa and should therefore be considered as an addition to randomized biopsies.

Identification of the variables associated with pain during transrectal ultrasonography-guided prostate biopsy in the era of periprostatic nerve block: the role of transrectal probe configuration

OBJECTIVE

To identify the different factors that are associated with pain perceived during transrectal ultrasonography (TRUS)-guided prostate biopsy (PBx), with special focus on the role of transrectal probe configuration.

PATIENTS AND METHODS

We analysed prospective data on 1114 patients undergoing TRUS-guided PBx at our institute from January 2007 to August 2010. Patients completed questionnaires based on a 10-point visual analogue pain scale related to the consecutive steps of PBx: probe insertion, application of periprostatic nerve block (PPNB) and the obtaining of PBx cores. The variables of interest were age, prostate volume, DRE findings, number of previous biopsies, probe type and the number of retrieved cores. All variables were correlated to pain scores using multivariate regression analysis.

RESULTS

At the probe insertion step, end-fire probes were more painful than side-fire probes. The Siemens G50 with metal, short plastic and long plastic needle guides (Siemens, Munich, Germany) had higher pain scores than the B&K probe (Bruel & Kjaer Medical, Copenhagen, Denmark; P = 0.09, 0.008 and 0.003, respectively). For pain at the PPNB application step, all G50(TM) guide subtypes and the Sonoline Prima probe (Siemens) had higher pain scores than the B&K probe, but this only reached statistical significance for the G50(TM) probe with short plastic guide (P = 0.03). On obtaining PBx cores, all G50(TM) subtypes had higher pain scores when compared with the B&K probe (P = 0.59, 0.38 and 0.69, respectively).

CONCLUSIONS

The probe design and needle guide affect pain during each step of TRUS-guided PBx. Both the B&K and Sonoline Prima probes caused less pain when compared with the G50(TM) probe, regardless of needle guide.

Repeat prostate biopsy strategies after initial negative biopsy: meta-regression comparing cancer detection of transperineal, transrectal saturation and MRI guided biopsy

Introduction

There is no consensus on how to investigate men with negative transrectal ultrasound guided prostate biopsy (TRUS-B) but ongoing suspicion of cancer. Three strategies used are transperineal (TP-B), transrectal saturation (TS-B) and MRI-guided biopsy (MRI-B). We compared cancer yields of these strategies.

Methods

Papers were identified by search of Pubmed, Embase and Ovid Medline. Included studies investigated biopsy diagnostic yield in men with at least one negative TRUS-B and ongoing suspicion of prostate cancer. Data including age, PSA, number of previous biopsy episodes, number of cores at re-biopsy, cancer yield, and Gleason score of detected cancers were extracted. Meta-regression analyses were used to analyse the data.

Results

Forty-six studies were included; 12 of TS-B, 14 of TP-B, and 20 of MRI-B, representing 4,657 patients. Mean patient age, PSA and number of previous biopsy episodes were similar between the strategies. The mean number of biopsy cores obtained by TP-B and TS-B were greater than MRI-B. Cancer detection rates were 30·0%, 36·8%, and 37·6% for TS-B, TP-B, and MRI-B respectively. Meta-regression analysis showed that MRI-B had significantly higher cancer detection than TS-B. There were no significant differences however between MRI-B and TP-B, or TP-B and TS-B. In a sensitivity analysis incorporating number of previous biopsy episodes (36 studies) the difference between MRI-B and TP-B was not maintained resulting in no significant difference in cancer detection between the groups. There were no significant differences in median Gleason scores detected comparing the three strategies.

Conclusions

In the re-biopsy setting, it is unclear which strategy offers the highest cancer detection rate. MRI-B may potentially detect more prostate cancers than other modalities and can achieve this with fewer biopsy cores. However, well–designed prospective studies with standardised outcome measures are needed to accurately compare modalities and define an optimum re-biopsy approach.

Is an initial saturation prostate biopsy scheme better than an extended scheme for detection of prostate cancer? A systematic review and meta-analysis

CONTEXT

The optimal initial prostate biopsy core number is still an issue with many unanswered questions and significant controversy.

OBJECTIVE

To compare diagnostic values of initial saturation prostate biopsy scheme and extended scheme with respect to prostate-specific antigen (PSA) levels, prostate volume (PV), and PSA density (PSAD).

EVIDENCE ACQUISITION

Electronic databases including Medline, Web of Knowledge, and the Cochrane Library were searched through November 1, 2012. Experts were consulted, and references from relevant articles were scanned. The meta-analysis was conducted with RevMan 5.1, according to the PRISMA guidelines. Mantel-Haenszel estimates were calculated and pooled under a fixed or random effect model, with data expressed as risk difference (RD) and 95% confidence interval (CI).

EVIDENCE SYNTHESIS

We analyzed eight trials with a total of 11997 participants who underwent transrectal ultrasound guided prostate biopsies for the first time and met inclusion criteria. Studies consisted of one paired design study, two randomized clinical trials, and five nonrandomized studies. Saturation biopsy scheme showed a significant advantage in prostate cancer (PCa) detection over an extended scheme (RD: 0.04; 95% CI, 0.01-0.08; p=0.02). In addition, subgroup analyses found a saturation protocol to be superior to an extended protocol in the detection of PCa in men with PSA <10 ng/ml (RD: 0.04; 95% CI, 0.01-0.07; p=0.002), PV >40 ml (RD: 0.05; 95%CI, 0.01-0.09; p=0.02), or PSAD <0.25 ng/ml per gram (RD: 0.04; 95% CI, 0.00-0.09; p=0.04).

CONCLUSIONS

The existing evidence indicates that an initial saturation biopsy scheme is more efficient than an extended scheme for PCa detection, especially for those men with lower PSA levels, higher PV, or lower PSAD, without increasing complications and the amount of insignificant cancer.

Impact of Real-Time Elastography versus Systematic Prostate Biopsy Method on Cancer Detection Rate in Men with a Serum Prostate-Specific Antigen between 2.5 and 10 ng/mL

The actual gold standard for the diagnosis of prostate cancer includes the serum prostate-specific antigen, the digital rectal examination, and the ultrasound-guided systematic prostate biopsy sampling. In the last years, the real-time elastography has been introduced as an imaging technique to increase the detection rate of prostate cancer and simultaneously reduce the number of biopsies sampled for a single patient. Here, we evaluated a consecutive series of 102 patients with negative digital-rectal examination and transrectal ultrasound, and prostate-specific antigen value ranging between 2.5 ng/mL and 10 ng/mL, in order to assess the impact of real-time elastography versus the systematic biopsy on the detection of prostate cancer. We found that only 1 out of 102 patients resulted true positive for prostate cancer when analysed with real-time elastography. In the other 6 cases, real-time elastography evidenced areas positive for prostate cancer, although additional neoplastic foci were found using systematic biopsy sampling in areas evidenced by real-time elastography as negative. Although additional studies are necessary for evaluating the effectiveness of this imaging technique, the present study indicates that the limited accuracy, sensitivity, and specificity do not justify the routine application of real-time elastography in prostate cancer detection.

Anatomy of the prostate revisited: implications for prostate biopsy and zonal origins of prostate cancer

Over the past 25 years, our understanding of prostatic disease has evolved secondary to the increased detection, treatment and study of both benign and neoplastic prostatic lesions. The advent of aggressive prostate-specific antigen screening and standardization of extended transrectal needle biopsy protocols has resulted in significant stage migration and earlier detection of prostate cancers, a growing proportion of which are lower-volume posterior peripheral zone tumours. Consequently, an increased incidence of anterior-predominant prostate cancers has been observed. Given the histomorphological complexity of the prostate, these developments have necessitated a reconsideration of prostatic anatomy, biopsy strategies in the detection of anterior tumours and the determination and relevance of zonal origin in prostate cancer. This review will provide a contemporary update of these topics, while highlighting specific areas in which a keen understanding of prostatic histoanatomy may influence biopsy interpretation.

Extended biopsy based criteria incorporating cumulative cancer length for predicting clinically insignificant prostate cancer

What's known on the subject? and What does the study add? The criteria used for selecting patients with prostate cancer for active surveillance (AS) are still not satisfactory due to the difficulty in predicting the significance of the prostate cancer. Urologists could predict insignificant prostate cancer by incorporating cumulative cancer length and biopsy Gleason score, derived from extended biopsy. The present study has added new criteria for predicting insignificant prostate cancer, which would lead to a better selection of candidates for AS.

OBJECTIVE

• To develop extended biopsy based criteria for predicting insignificant cancer (IC) using extended biopsy findings.

PATIENTS AND METHODS

• From 2000 to 2009, 1575 patients with prostate cancer were primarily treated by radical prostatectomy in two referral hospitals. • Of these, the study cohort comprised 499 patients with extended biopsy confirmed, clinically organ-confined (cT1-2N0M0) prostate cancer with PSA levels of <20 ng/mL. • Cancer information obtained through extended biopsy included cumulative cancer length (CCL) divided by the number of biopsy cores (CCL/core).

RESULTS

• Pathological examination revealed 39 ICs (7.8%). All these ICs fell in a category of prostate cancer with clinical stage ≤ T2a and 2005 International Society of Urological Pathology Consensus Conference (ISUP) modified biopsy Gleason score ≤ 7. • Accordingly, we analysed predictors of IC in a subset cohort of 370 patients in this category. A multivariate logistic regression analysis revealed that 2005 ISUP modified biopsy Gleason score and CCL/core were independently significant predictors of IC. • We determined a threshold value of CCL/core of 0.20 mm for predicting IC using receiver operating characteristic analysis. • Based on these findings, we developed simple extended biopsy based criteria for predicting IC as follows: (i) PSA level of <20 ng/mL; (ii) Clinical stage ≤ T2a; (iii) 2005 ISUP modified biopsy Gleason score ≤ 6; (iv) CCL/core of <0.20 mm. • The specificity of the criteria was 91%, which was significantly higher than the value from a subset of criteria without item iv (P < 0.001).

CONCLUSION

• We have developed extended biopsy based criteria for predicting IC incorporating the 2005 ISUP modified biopsy Gleason score and CCL/core.

Diagnosis of isolated high-grade prostatic intra-epithelial neoplasia: proposal of a nomogram for the prediction of cancer detection at saturation re-biopsy

Study Type--Diagnostic (case series). Level of Evidence 4. What's known on the subject? And what does the study add? Multifocality, age, PSA values, and biopsy protocols regarding the predictive value of high grade PIN have been discussed extensively in the literature. Our study developed for the first time a predictive nomogram that could be helpful for patient counselling and to guide the urologist to perform rPBX after an initial diagnosis of isolated HGPIN.

OBJECTIVE

• To evaluate factors that may predict prostate cancer (PCa) detection after the initial diagnosis of high-grade prostatic intra-epithelial neoplasia (HGPIN) on prostate biopsy (PBx) with six to 24 random cores.

PATIENTS AND METHODS

• We retrospectively evaluated 262 patients submitted from 1998 to 2007 to prostate re-biopsy (rPBx) after an initial HGPIN diagnosis in tertiary academic centres. • HGPIN diagnosis was obtained on initial systematic PBx with six to 24 random cores. • All patients were re-biopsied with a 'saturation' rPBx with 20-26 cores, with a median time to rPBx of 12 months. • All slides were reviewed by expert uropathologists.

RESULTS

• Plurifocal HGPIN (pHGPIN) was found in 115 patients and monofocal HGPIN (mHGPIN) was found in 147 patients. • In total, 108 and 154 patients, respectively, were submitted to >12-core initial PBx and ≤12-core initial PBx. • Overall PCa detection at rPBx was 31.7%. PSA level (7.7 vs 6.6 ng/mL; P= 0.031) and age (68 vs 64 years; P= 0.001) were significantly higher in patients with PCa at rPBx. • PCa detection was significantly higher in patients with a ≤12-core initial PBx than in those with a >12-core initial PBx (37.6% vs 23.1%; P= 0.01), as well as in patients with pHGPIN than in those with mHGPIN (40% vs 25.1%; P= 0.013). • At multivariable analysis, PSA level (P= 0.041; hazards ratio, HR, 1.08), age (P < 0.001; HR, 1.09), pHGPIN (P= 0.031; HR, 1.97) and ≤12-core initial PBx (P= 0.012; HR, 1.95) were independent predictors of PCa detection. • A nomogram including these four variables achieved 72% accuracy for predicting PCa detection after an initial HGPIN diagnosis.

CONCLUSIONS

• PCa detection on saturation rPBx after an initial diagnosis of HGPIN is significantly higher in patients with a ≤12-core initial PBx than those with a >12-core initial PBx and in patients with pHGPIN than in those with mHGPIN. • We developed a simple prognostic tool for the prediction of PCa detection in patients with initial HGPIN diagnosis who were undergoing saturation rPBx.

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.

Extended sampling at first biopsy improves cancer detection rate: results of a prospective, randomized trial comparing 12 versus 18-core prostate biopsy

PURPOSE

We determined whether increasing the number of cores at first prostate biopsy would improve the cancer detection rate without increasing the detection of clinically insignificant tumors.

MATERIALS AND METHODS

From January 2009 to January 2010 patients scheduled for prostate biopsy were randomized to 12 or 18-core sampling. Study inclusion criteria were 1) age 45 to 75 years, 2) abnormal digital rectal examination and/or prostate specific antigen 4 to 20 ng/ml, and 3) no previous biopsy. The primary end point was the cancer detection rate. Secondary end points were clinically insignificant cancer detection and morbidity.

RESULTS

A total of 150 patients were enrolled in the study. Preoperative variables were similar in the 2 groups of 75 patients each. Cancer was detected in 23 patients (30.7%) in group 1 and in 36 (48%) in group 2 (p = 0.02). More cases of insignificant cancer were detected in group 2 (p not significant). In men with prostate volume 65 cc or less the detection rate was 30.9% in group 1 and 52.8% in group 2 (p = 0.02). In men with prostate specific antigen 10 ng/ml or less the detection rate was 19.6% in group 1 and 38.4% in group 2 (p = 0.03). Two group 2 patients (5.5%) were diagnosed based on additional samples but the diagnosis corresponded to insignificant cancer. There was no statistically significant difference in morbidity.

CONCLUSIONS

The 18-core protocol improves prostate cancer detection without increasing morbidity. Results suggest that the 12-core biopsy protocol is adequate for prostate cancer detection at first biopsy.

Prediction of prostate cancer in unscreened men: external validation of a risk calculator

BACKGROUND

Prediction models need external validation to assess their value beyond the setting where the model was derived from.

OBJECTIVE

To assess the external validity of the European Randomized study of Screening for Prostate Cancer (ERSPC) risk calculator (www.prostatecancer-riskcalculator.com) for the probability of having a positive prostate biopsy (P(posb)).

DESIGN, SETTING AND PARTICIPANTS

The ERSPC risk calculator was based on data of the initial screening round of the ERSPC section Rotterdam and validated in 1825 and 531 men biopsied at the initial screening round in the Finnish and Swedish sections of the ERSPC respectively. P(posb) was calculated using serum prostate specific antigen (PSA), outcome of digital rectal examination (DRE), transrectal ultrasound and ultrasound assessed prostate volume.

MEASUREMENTS

The external validity was assessed for the presence of cancer at biopsy by calibration (agreement between observed and predicted outcomes), discrimination (separation of those with and without cancer), and decision curves (for clinical usefulness).

RESULTS AND LIMITATIONS

Prostate cancer was detected in 469 men (26%) of the Finnish cohort and in 124 men (23%) of the Swedish cohort. Systematic miscalibration was present in both cohorts (mean predicted probability 34% versus 26% observed, and 29% versus 23% observed, both p<0.001). The areas under the curves were 0.76 and 0.78, and substantially lower for the model with PSA only (0.64 and 0.68 respectively). The model proved clinically useful for any decision threshold compared with a model with PSA only, PSA and DRE, or biopsying all men. A limitation is that the model is based on sextant biopsies results.

CONCLUSIONS

The ERSPC risk calculator discriminated well between those with and without prostate cancer among initially screened men, but overestimated the risk of a positive biopsy. Further research is necessary to assess the performance and applicability of the ERSPC risk calculator when a clinical setting is considered rather than a screening setting.

Beyond diagnosis: evolving prostate biopsy in the era of focal therapy

Despite decades of use as the “gold standard” in the detection of prostate cancer, the optimal biopsy regimen is still not universally agreed upon. While important aspects such as the need for laterally placed biopsies and the importance of apical cancer are known, repeated studies have shown significant patients with cancer on subsequent biopsy when the original biopsy was negative and an ongoing suspicion of cancer remained. Attempts to maximise the effectiveness of repeat biopsies have given rise to the alternate approaches of saturation biopsy and the transperineal approach. Recent interest in focal treatment of prostate cancer has further highlighted the need for accurate detection of prostate cancer, and in response, the introduction of transperineal template-guided biopsy. While the saturation biopsy approach and the transperineal template approach increase the detection rate of cancer in men with a previous negative biopsy and appear to have acceptable morbidity, there is a lack of clinical trials evaluating the different biopsy strategies. This paper reviews the evolution of prostatic biopsy and current controversies.