Extended and saturation needle biopsy for the diagnosis of prostate cancer

How Many Cores Should Be Sampled during Systematic Prostate Biopsy in Case of Negative Multiparametric Magnetic Resonance Imaging? Analysis of 274 Men with Clinical Suspicion of Prostate Cancer

INTRODUCTION

This study aimed to investigate the number of cores needed in a systematic biopsy (SB) in men with clinical suspicion of prostate cancer (PCa) but negative prebiopsy multiparametric magnetic resonance imaging and to test prostate-specific antigen (PSA) density as an indicator for reduced SB.

METHODS

Two hundred and seventy-four patients were analyzed, extracted from an institutional database. Detection rates of any PCa and clinically significant (CS) PCa for different reduced biopsy protocols were compared by using Fisher's exact test.

RESULTS

In total, 12-core SB revealed PCa in 103 (37.6%) men. Detection rates of reduced biopsy protocols were 74 (27%, 6-core) and 82 (29.9%, 8-core). Regarding CSPCa, 12-core SB revealed a detection rate of 26 (9.5%). Reduced biopsy protocols detected less CSPCa: 15 (5.5%) and 18 (6.6%), respectively. All differences were statistically significant, p < 0.05. PSA density ≥0.15 did not help to filter out men in whom a reduced biopsy may be sufficient.

CONCLUSIONS

Twelve-core SB still has the highest detection rate of any PCa and CSPCa compared to reduced biopsy protocols. If the investigator and patient agree - based on individual risk calculation - to perform a biopsy, this SB should contain at least 12 cores regardless of PSA density.

Spatial distribution of biopsy cores and the detection of intra-lesion pathologic heterogeneity

Objectives:

The objective of this study was to determine if spatial distribution of multiparametric magnetic resonance imaging–transrectal ultrasound (mpMRI-TRUS) fusion biopsy cores to the index lesion reveals trends in the detection of intra-lesion Gleason heterogeneity and a more optimal prostate biopsy strategy.

Methods:

Index lesion was the lesion with longest diameter on T2-weighted (T2W)-MRI. In cohort 1, fusion biopsy cores biopsies were taken in areas in the center of the target as well as 1 cm laterally on each side. For cohort 2, targeted biopsies were taken from the center of the lesion only. Heterogeneity was defined as difference in maximum Gleason score obtained from fusion cores in the center of the index lesion versus cores obtained from the periphery (cohort 1), or any difference in maximum Gleason score obtained from fusion cores targeted to the index lesion (cohort 2) compared with systematic 12 cores TRUS biopsy.

Results:

Ninety-nine consecutive patients (35 and 64 in cohorts 1 and 2, respectively) with median age (SD) and prostate-specific antigen (PSA) of 66.9 (±5.9) and 9.7 (±8.2) respectively, were included. Age, PSA, Prostate Imaging Reporting and Data System (PI-RADS) score, and preoperative MRI lesion size were not significantly different between cohorts. Gleason heterogeneity was observed at a significantly higher rate in cohort 1 versus cohort 2 (58% versus 24%; p = 0.041). In cohort 1, cores obtained from the center of the lesion had higher Gleason score than cores obtained from the periphery of the targeted lesion in 57% of cases.

Conclusions:

We demonstrate that there is observable tumor heterogeneity in biopsy specimens, and that increased number of cores, as well as cores focused on the center and periphery of the largest lesion in the prostate, provide more comprehensive diagnostic information about the patient’s clinical risk category than taking nonspecific cores targeted within the tumor.

Low risk patients benefit from extreme anterior apical sampling on initial biopsy for prostate cancer diagnosis

BACKGROUND

To assess the effect of additional extreme apical sampling on prostate cancer (PCa) detection and aggressiveness in patients with standard risk versus high risk of a positive biopsy.

METHODS

Three thousand fifty three men were reviewed from our institution review board approved prostate biopsy database. Two thousand five hundred and twenty one underwent biopsy with 12 cores while 532 underwent 14 core sampling (2 extra cores from the extreme anterior apex). Patients were stratified into one of two risk groups: (1) standard risk of PCa (elevated prostate specific antigen (PSA) < 10 ng/ml, normal digital rectal exam (DRE), and no lesions on transrectal ultrasound (TRUS)), and (2) higher risk of PCa (PSA > 10 ng/ml and/or abnormal DRE and/or lesion on TRUS). Prostate cancer detection and disease characteristics were compared between the biopsy schemes stratified by risk of a positive biopsy.

RESULTS

PCa detection with 14 core sampling was more likely in all patients (OR 1.339, 95% CL 1.070-1.676) and in men with standard risk (OR 1.334, 95% CL 1.007-1.769). A greater median number of positive cores (3 vs. 2) and a higher maximum cancer % per core (40% vs. 25%) were seen in the 14 core cohort when stratified to standard risk. Gleason ≥7 was more likely detected with 14 cores in the standard risk group (55.6% vs. 45.2%). Differences in PCa detection and Gleason ≥7 between biopsy techniques were not noted in the higher risk group.

CONCLUSION

Extreme apical sampling increases aggressive cancer detection on initial biopsy, especially in patients with standard risk of PCa.

Optimization of initial prostate biopsy in clinical practice: sampling, labeling and specimen processing

PURPOSE

An optimal prostate biopsy in clinical practice is based on a balance among adequate detection of clinically significant prostate cancers (sensitivity), assuredness regarding the accuracy of negative sampling (negative predictive value), limited detection of clinically insignificant cancers and good concordance with whole gland surgical pathology results to allow accurate risk stratification and disease localization for treatment selection. Inherent within this optimization is variation of the core number, location, labeling and processing for pathological evaluation. To date, there is no consensus in this regard. The purpose of this review is to 1) define the optimal number and location of biopsy cores during primary prostate biopsy among men with suspected prostate cancer, 2) define the optimal method of labeling prostate biopsy cores for pathological processing which will provide relevant and necessary clinical information for all potential clinical scenarios, and 3) determine the maximal number of prostate biopsy cores allowable within a specimen jar which would not preclude accurate histological evaluation of the tissue.

MATERIALS AND METHODS

A bibliographic search using PubMed® covering the period up to July 2012 yielded approximately 550 articles. Articles were reviewed and categorized based on which of the 3 objectives of this review was addressed. Data were extracted, analyzed and summarized. Recommendations are provided based on this literature review and our clinical experience.

RESULTS

The use of 10 to 12-core extended sampling protocols increases cancer detection rates compared to traditional sextant sampling methods and reduces the likelihood of repeat biopsy by increasing negative predictive value, ultimately allowing more accurate risk stratification without increasing the likelihood of detecting insignificant cancers. As the number of cores increases above 12, the increase in diagnostic yield becomes marginal. Only limited evidence supports the use of initial biopsy schemes involving more than 12 cores or saturation. Apical and laterally directed sampling of the peripheral zone increases cancer detection rate, reduces the need for repeat biopsies and predicts pathological features on prostatectomy while transition zone biopsies do not. There are little data to suggest that knowing the exact site of an individual positive biopsy core provides meaningful clinical information. However, determining laterality of cancer on biopsy may be helpful for predicting sites of extracapsular extension and therapeutic planning. Placement of multiple biopsy cores in a single container (greater than 2) appears to compromise pathological evaluation, which can reduce cancer detection rate and increase the likelihood of equivocal diagnoses.

CONCLUSIONS

A 12-core systematic biopsy that incorporates apical and far-lateral cores in the template distribution allows maximal cancer detection, avoids repeat biopsy, and provides information adequate for identifying men who need therapy and planning that therapy while minimizing the detection of occult, indolent prostate cancers. This literature review does not provide compelling evidence that individual site specific labeling of cores benefits clinical decision making regarding the management of prostate cancer. Based on the available literature, we recommend packaging no more than 2 cores in each jar to avoid reduction of the cancer detection rate through inadequate tissue sampling.

Prostate saturation biopsy following a first negative biopsy: state of the art

INTRODUCTION

Saturation prostate biopsy (SPBx) has been initially introduced to improve prostate cancer (PCa) detection rate (DR) in the repeat setting. Nevertheless, the optimal number and the most appropriate location of the cores, together with the timing to perform a second PBx and the eventual modification of the PBx protocols according to the different clinical situations, are matters of debate. The aim of this review is to perform a critical analysis of the literature about the actual role of SPBx in the repeat setting.

MATERIALS AND METHODS

We performed a systematic review of the literature since 1995 up to 2011. Electronic searches were limited to the English language, using the MEDLINE database. The key words 'saturation prostate biopsy' and 'repeated prostate biopsy' were used.

RESULTS

SPBx improves PCa DR if clinical suspicion persists after previous biopsy with negative findings and provides an accurate prediction of prostate tumor volume and grade, even if the issue about the number and locations of the cores is still a matter of debate.

CONCLUSIONS

At present, SPBx seems to be really necessary in men with persistent suspicion of PCa after negative initial biopsy and probably in patients with a multifocal high-grade prostatic intraepithelial neoplasia or atypical small acinar proliferation. In the remaining situations, adopting an individualized scheme is preferable.

Supervised regularized canonical correlation analysis: integrating histologic and proteomic measurements for predicting biochemical recurrence following prostate surgery

BACKGROUND

Multimodal data, especially imaging and non-imaging data, is being routinely acquired in the context of disease diagnostics; however, computational challenges have limited the ability to quantitatively integrate imaging and non-imaging data channels with different dimensionalities and scales. To the best of our knowledge relatively few attempts have been made to quantitatively fuse such data to construct classifiers and none have attempted to quantitatively combine histology (imaging) and proteomic (non-imaging) measurements for making diagnostic and prognostic predictions. The objective of this work is to create a common subspace to simultaneously accommodate both the imaging and non-imaging data (and hence data corresponding to different scales and dimensionalities), called a metaspace. This metaspace can be used to build a meta-classifier that produces better classification results than a classifier that is based on a single modality alone. Canonical Correlation Analysis (CCA) and Regularized CCA (RCCA) are statistical techniques that extract correlations between two modes of data to construct a homogeneous, uniform representation of heterogeneous data channels. In this paper, we present a novel modification to CCA and RCCA, Supervised Regularized Canonical Correlation Analysis (SRCCA), that (1) enables the quantitative integration of data from multiple modalities using a feature selection scheme, (2) is regularized, and (3) is computationally cheap. We leverage this SRCCA framework towards the fusion of proteomic and histologic image signatures for identifying prostate cancer patients at the risk of 5 year biochemical recurrence following radical prostatectomy.

RESULTS

A cohort of 19 grade, stage matched prostate cancer patients, all of whom had radical prostatectomy, including 10 of whom had biochemical recurrence within 5 years of surgery and 9 of whom did not, were considered in this study. The aim was to construct a lower fused dimensional metaspace comprising both the histological and proteomic measurements obtained from the site of the dominant nodule on the surgical specimen. In conjunction with SRCCA, a random forest classifier was able to identify prostate cancer patients, who developed biochemical recurrence within 5 years, with a maximum classification accuracy of 93%.

CONCLUSIONS

The classifier performance in the SRCCA space was found to be statistically significantly higher compared to the fused data representations obtained, not only from CCA and RCCA, but also two other statistical techniques called Principal Component Analysis and Partial Least Squares Regression. These results suggest that SRCCA is a computationally efficient and a highly accurate scheme for representing multimodal (histologic and proteomic) data in a metaspace and that it could be used to construct fused biomarkers for predicting disease recurrence and prognosis.

H HRMAS NMR Derived Bio-markers Related to Tumor Grade, Tumor Cell Fraction, and Cell Proliferation in Prostate Tissue Samples

A high-resolution magic angle spinning NMR spectroscopic approach is presented for evaluating the occurrence, amount and aggressiveness of cancer in human prostate tissue samples. Using this technique, key metabolites in malignant and non-malignant samples (n = 149) were identified, and patterns of their relative abundance were analyzed by multivariate statistical methods. Ratios of various metabolites – including (glycerophophorylcholine + phosphorylcholine)/creatine, myo-inositol/scyllo-inositol, scyllo-inositol/creatine, choline/creatine, and citrate/creatine – correlated with: i) for non-malignant tissue samples, the distance to the nearest tumor and its Gleason score and; ii) the fraction of tumor cells present in the sample; and iii) tumor cell proliferation (Ki67 labelling index). This NMR-based approach allows the extraction of information that could be useful for developing novel diagnostic methods for prostate cancer.

Optimizing performance and interpretation of prostate biopsy: a critical analysis of the literature

CONTEXT

The number and location of biopsy cores and the interpretation of prostate biopsy in different clinical settings remain the subjects of continuing debate.

OBJECTIVE

Our aim was to review the current evidence regarding the performance and interpretation of initial, repeat, and saturation prostatic biopsy.

EVIDENCE ACQUISITION

A comprehensive Medline search was performed using the Medical Subject Heading search terms prostate biopsy, prostate cancer, detection, transrectal ultrasound (TRUS), nomogram, and diagnosis. Results were restricted to the English language, with preference given to those published within the last 3 yr.

EVIDENCE SYNTHESIS

At initial biopsy, a minimum of 10 but not >18 systematic cores are recommended, with 14-18 cores in glands ≥ 50 cm³. Biopsies should be directed laterally, and transition zone (TZ) cores are not recommended in the initial biopsy setting. Further biopsy sets, either as an extended repeat or as a saturation biopsy (≥ 20 cores) including the TZ, are warranted in young and fit men with a persistent suspicion of prostate cancer. An immediate repeat biopsy is not indicated for prior high-grade prostatic intraepithelial neoplasia diagnosis given an adequate extended initial biopsy. Conversely, biopsies with atypical glands that are suspicious but not diagnostic of cancer should be repeated within 3-6 mo. Overall recommendations for further biopsy sets (a third set or more) cannot be made. Transrectal ultrasound-guided systematic biopsies represent the standard-of-care method of prostate sampling. However, transperineal biopsies are an up-to-standard alternative.

CONCLUSIONS

The optimal prostatic biopsy regimen should be based on the individualized clinical setting of the patient and should follow the minimum standard requirements reported in this paper.

[Saturation biopsy in prostate cancer diagnosis]

AIMS

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

RESULTS

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

CONCLUSIONS

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

A novel gene signature for molecular diagnosis of human prostate cancer by RT-qPCR

BACKGROUND

Prostate cancer (CaP) is one of the most relevant causes of cancer death in Western Countries. Although detection of CaP at early curable stage is highly desirable, actual screening methods present limitations and new molecular approaches are needed. Gene expression analysis increases our knowledge about the biology of CaP and may render novel molecular tools, but the identification of accurate biomarkers for reliable molecular diagnosis is a real challenge. We describe here the diagnostic power of a novel 8-genes signature: ornithine decarboxylase (ODC), ornithine decarboxylase antizyme (OAZ), adenosylmethionine decarboxylase (AdoMetDC), spermidine/spermine N(1)-acetyltransferase (SSAT), histone H3 (H3), growth arrest specific gene (GAS1), glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and Clusterin (CLU) in tumour detection/classification of human CaP.

METHODOLOGY/PRINCIPAL FINDINGS

The 8-gene signature was detected by retrotranscription real-time quantitative PCR (RT-qPCR) in frozen prostate surgical specimens obtained from 41 patients diagnosed with CaP and recommended to undergo radical prostatectomy (RP). No therapy was given to patients at any time before RP. The bio-bank used for the study consisted of 66 specimens: 44 were benign-CaP paired from the same patient. Thirty-five were classified as benign and 31 as CaP after final pathological examination. Only molecular data were used for classification of specimens. The Nearest Neighbour (NN) classifier was used in order to discriminate CaP from benign tissue. Validation of final results was obtained with 10-fold cross-validation procedure. CaP versus benign specimens were discriminated with (80+/-5)% accuracy, (81+/-6)% sensitivity and (78+/-7)% specificity. The method also correctly classified 71% of patients with Gleason score<7 versus > or =7, an important predictor of final outcome.

CONCLUSIONS/SIGNIFICANCE

The method showed high sensitivity in a collection of specimens in which a significant portion of the total (13/31, equal to 42%) was considered CaP on the basis of having less than 15% of cancer cells. This result supports the notion of the "cancer field effect", in which transformed cells extend beyond morphologically evident tumour. The molecular diagnosis method here described is objective and less subjected to human error. Although further confirmations are needed, this method poses the potential to enhance conventional diagnosis.

Computerized transrectal ultrasound (C-TRUS) of the prostate: detection of cancer in patients with multiple negative systematic random biopsies

This study was designed to compare the diagnostic yield of computerized transrectal ultrasound (C-TRUS) guided biopsies in the detection of prostate cancer in a group of men with a history of multiple systematic random biopsies with no prior evidence of prostate cancer. The question was asked: Can we detect cancer by C-TRUS that has been overlooked by multiple systematic biopsies? The entrance criteria for this study were prior negative systematic random biopsies regardless of number of biopsy sessions or number of individual biopsy cores. Serial static TRUS images were evaluated by C-TRUS, which assessed signal information independent of visual gray scale. Five C-TRUS algorithms were utilized to evaluate the information of the ultrasound signal. Interpretation of the results were documented and the most suspicious regions marked by C-TRUS were biopsied by guiding the needle to the marked location. Five hundred and forty men were biopsied because of an elevated PSA or abnormal digital rectal exam. 132 had a history of prior negative systematic random biopsies (1-7 sessions, median: 2 and between 6 and 72 individual prostate biopsies, median: 12 cores). Additionally, a diagnostic TUR-P of the prostate with benign result was performed in four patients. The PSA ranged from 3.1-36 ng/ml with a median of 9.01 ng/ml. The prostate volume ranged from 6-203 ml with a median of 42 ml. Of the 132 patients with prior negative systematic random biopsies, cancer was found in 66 (50%) by C-TRUS targeted biopsies. In this group the median number of negative biopsy sessions was two and a median of 12 biopsy cores were performed. From literature we would expect a cancer detection rate in this group with systematic biopsies of approximately 7%. We only found five carcinomas with a Gleason Score (GS) of 5, 25 with GS 6, 22 with GS 7, 8 with GS 8 and even 7 with GS 9. The results of this prospective clinical trail indicates that the additional use of the C-TRUS identifies clinical significant cancerous lesions that could not been visualized or detected by systematic random biopsies in a very high percentage. In addition, the results of the study support the efforts to search for strategies that utilize expertise and refinement of imaging modalities rather than elevating the number of random biopsies (f.e. 141 cores in one session) in the detection of prostate cancer.

Urologic imaging for localized prostate cancer in 2007

Increasing numbers of systematic random biopsies have virtually replaced urologic imaging as a detection and staging tool in prostate cancer. TRUS as the most commonly utilized urologic imaging is now mainly utilized to guide the biopsy needle into the correct anatomical or topographic region of the prostate. But even multiple systematic random biopsies have been shown to overlook a large number of clinically significant carcinoma. This fact has led to a dramatic increase in the number of biopsies taken in the detection of localized prostate cancer. There are some centers where 6, 10, 12, even up to 143 biopsies are taken in one sitting. This increasingly invasive and heterogeneous strategy underlines the need for an improvement in diagnostic imaging. New modalities and innovative techniques are currently being investigated in order to identify prostate cancer more accurately. The purpose of this paper is to review innovative urologic imaging techniques to identify emerging modalities that may be beneficial in the management of prostate cancer. Enhanced transrectal ultrasonography modalities, including ultrasound contrast agents, color and power doppler, elastography and computerized (C)-TRUS with artificial neural network analysis (ANNA) promise benefits in comparison to standard gray-scale ultrasonography to accurately target and diagnose prostate cancer.

[Innovative approaches in prostate cancer ultrasound]

Today, systematic random biopsies have virtually replaced ultrasound as an imaging tool in the early diagnosis and staging of prostate cancer. Transrectal ultrasonography (TRUS) is now utilized almost only to guide the biopsy needle into the correct anatomical or topographical region of the prostate. Nevertheless, a large number of clinically significant carcinomas are not discovered despite of multiple systematic biopsies. This has led to a dramatic increase in the number of biopsy samples taken, with 6, 10, 12 to 143 being taken during one session depending on the site. Newer modalities and innovative techniques are being investigated in order to accurately identify patients with prostate cancer at different stages of the disease. Innovative ultrasonography techniques may improve the diagnosis and staging of current imaging techniques.

Do all patients with high-grade prostatic intraepithelial neoplasia on initial prostatic biopsy eventually progress to clinical prostate cancer?

OBJECTIVE

To assess the clinical outcome of patients with a diagnosis of high-grade prostatic intraepithelial neoplasia (PIN) on initial prostatic biopsy, with a minimum of 5 years of follow-up, as such patients are at greater risk of having prostate cancer on subsequent biopsy.

PATIENTS AND METHODS

Between November 1992 and October 1998, 21 patients were identified as having PIN on their initial transrectal ultrasonography-guided prostate biopsy. None of these patients had a focus of cancer on the initial biopsy. Their medical data were reviewed retrospectively to determine the natural history of PIN in these patients. Patients who were not identified as having cancer were followed every 6-12 months with prostate-specific antigen (PSA) testing and digital rectal examinations (DRE).

RESULTS

A mean (range) of 7 (2-8) cores were taken at initial biopsy; the mean age of the patients was 63 (53-77) years and mean PSA level 9.1 (4.9-17.6) ng/mL. Six patients had an abnormal DRE at presentation. A mean of 8 (7-10) cores were obtained on the second biopsy; six patients were diagnosed with cancer, with a mean Gleason score of 6 (5-7), while three were diagnosed with persistent PIN. These three patients had a third prostate biopsy which showed cancer of Gleason score 6 in one and benign prostatic hyperplasia in two. After a mean follow-up of 72.2 (60-84) months, none of the remaining 12 patients was diagnosed with clinically significant cancer. Five of these patients went on to a third prostate biopsy, with no evidence of cancer. One patient died from unrelated causes during this period.

CONCLUSION

This study affirms our current practice of following patients with PIN conservatively if a second or third subsequent prostate biopsy is negative. Whether PIN is a premalignant lesion or merely a lesion associated with cancer needs to be addressed in multicentre studies with a follow-up of > 10 years.

Transrectal ultrasound guided biopsy of the prostate: random sextant versus biopsies of sono-morphologically suspicious lesions

Transrectal ultrasound (TRUS) guided multiple systematic random biopsies are presently the method of choice for determining the presence or absence of prostate cancer. TRUS image information is only used to guide the biopsy needle into the prostate, but not to localize and target cancerous lesions. Our aim in this study was to evaluated the possible predictive value of tumor suspicious endosonographic lesions of the prostate for prostate biopsies. We prospectively compared six systematic biopsies with lesion guided biopsies in a consecutive series of 217 patients. All patients had a prostate specific antigen (PSA) level of >4 ng/ml without a history of prostate disease. In a subgroup of 145 men with sonomorphologic lesions suggestive for prostate cancer (hypoechoic areas or asymmetries predominantly in the peripheral zone), lesion-guided biopsies were taken in addition to the systematic biopsies. We evaluated the number of tumors which were diagnosed or missed by both of the biopsy strategies. Of the 217 evaluated patients, 64 (29%) had histology confirmed cancer. Four patients with negative sextant biopsies had a positive TRUS guided biopsy. Out of 145 patients with a normal TRUS, three were cancer positive by sextant biopsy. A total of 1,387 individual biopsy cores were evaluated. Of the 1,304 systematic biopsy cores, 182 (14%) were positive and 1,122 (86%) negative. Of the 329 TRUS lesion guided biopsy cores 139 (42%) were positive and 190 (58%) negative. Patients with tumor suggestive TRUS lesions have a considerably higher risk of being diagnosed with prostate cancer compared to patients without such lesions. Both systematic sextant and TRUS lesion guided biopsies missed detectable prostate cancer in a minority of patients. Taking the endosonographic morphology of the prostate gland into consideration for biopsy strategies may improve the quality of the biopsy and avoid unnecessary invasive procedures in selected cases.

Computergest�tzter transrektaler Ultraschall (C-TRUS) in der Diagnostik des Prostatakarzinoms

In the diagnosis of prostate cancer digital rectal examination and transrectal ultrasound (TRUS) are the most utilized methods for clinical evaluation. However, both methods are not able to differentiate between benign and malignant findings with a high amount of certainty. Nevertheless, TRUS is an excellent tool to guide biopsies in practically any region of the prostate. The most significant problem of visual TRUS interpretation is the lack of specificity, especially being an inexperienced user. In order to enhance the diagnostic capabilities of TRUS we developed a computerized analysis of the TRUS signal information (C-TRUS/ANNA), which was validated by the pathohistologic findings of radical prostatectomies. The question was asked: Can C-TRUS detect cancer that has been missed by even multiple systematic biopsies? The entrance criteria was prior negative systematic random biopsies regardless of number of biopsy sessions or number of individual biopsy cores. Five C-TRUS subvisual algorithms were utilized to evaluate the information of the ultrasound signal. The most suspicious regions were marked by C-TRUS and biopsied by guiding a needle into that specific location. In this study 132 with a history of 6-72 negative systematic random biopsies (median: 12 cores) were evaluated by C-TRUS. The PSA ranged from 3.1-36 ng/ml with a median of 9.01 ng/ml. C-TRUS detected in 66 (50%) of these 132 patients cancer by targeted biopsies. In thes 66 men the median number of negative biopsy sessions were two and a median of 12 biopsy cores had been taken. From the literature, we would expect a cancer detection rate in this group with systematic sextant biopsies of about 7%. Only five of the detected carcinomas showed a Gleason Score (GS) of 5, were as 25 had a GS of 6, 22 a GS of 7 and 15 a GS above 7. The results of this prospective clinical trail indicate that C-TRUS is able to identify clinically significant cancers that were missed by even multiple systematic random biopsies. In addition, the concept of searching for strategies that utilize expertise and refinement of imaging modalities is supported rather than just elevating the number of random biopsies (i.e. 141 cores in one session).