Micro-Focal Prostate Cancer: A Comparison of Biopsy and Radical Prostatectomy Specimen Features

Immunohistochemistry for Prostate Biopsy-Impact on Histological Prostate Cancer Diagnoses and Clinical Decision Making

BACKGROUND

To test the value of immunohistochemistry (IHC) staining in prostate biopsies for changes in biopsy results and its impact on treatment decision-making.

METHODS

Between January 2017-June 2020, all patients undergoing prostate biopsies were identified and evaluated regarding additional IHC staining for diagnostic purpose. Final pathologic results after radical prostatectomy (RP) were analyzed regarding the effect of IHC at biopsy.

RESULTS

Of 606 biopsies, 350 (58.7%) received additional IHC staining. Of those, prostate cancer (PCa) was found in 208 patients (59.4%); while in 142 patients (40.6%), PCa could be ruled out through IHC. IHC patients harbored significantly more often Gleason 6 in biopsy (p < 0.01) and less suspicious baseline characteristics than patients without IHC. Of 185 patients with positive IHC and PCa detection, IHC led to a change in biopsy results in 81 (43.8%) patients. Of these patients with changes in biopsy results due to IHC, 42 (51.9%) underwent RP with 59.5% harboring ≥pT3 and/or Gleason 7-10.

CONCLUSIONS

Patients with IHC stains had less suspicious characteristics than patients without IHC. Moreover, in patients with positive IHC and PCa detection, a change in biopsy results was observed in >40%. Patients with changes in biopsy results partly underwent RP, in which 60% harbored significant PCa.

Pathological correlation between prostate biopsies and the radical prostatectomy, about 30 cases

Background

Since the advent of the massive prostate-specific antigen (PSA) testing, prostate cancer has become a major public health problem. It is currently the most common cancer and the second leading cause of cancer death in men. The diagnosis is based on the histopathological study of prostate biopsies. The aim of our work was to study the correlation of the grade group (GG) using the ISUP 2016 classification between the prostate needle biopsies and radical prostatectomy specimen.

Methods

This was a retrospective study of 30 patients. We studied the correlation of the grade group (GG) according to the new classification ISUP (2016) between prostate biopsies and radical prostatectomy specimen.

Results

The average age of our patients was 65 years, the diagnosis was discovered on an individual screening in 15% of the cases, and 65% of our patients were diagnosed with LUTS due to an associated benign prostatic hyperplasia. The average PSA level in our study was 11 ng/ml. In the biopsies group, the grade 1 and 2 groups were in the majority with 40% of the cases each of them. We noted that GG 3 (Gleason 4 + 3) was represented in 16.66% of cases, while GG4 was only present in 3% of cases. On the prostatectomy specimen group, GG1 was represented in 33.33% of cases, GG2 in 40% of cases and GG3 in 20% of cases. GG4 was represented in 6.66% of cases. Among GG1 patients, identical staging was noted in 75% of cases, and under-staging in 25% of cases. For GG2 patients, over-staging in 8.3% of cases, identical staging in 83.3% of cases and under-staging of 8.3%. Among GG 3 patients, there was an 80% identical staging, while an under-staging was present in 20% of cases. The GG 4 is perfectly correlated. Combining all groups in our study, we noted an exact staging in 80% of the cases, an under-staging in 16.33% of the cases, and an over-staging in 3.33% of the cases. The Kappa concordance index was 0.4.

Conclusions

The correlation of the grade group between the prostate biopsies and the radical prostatectomy specimen was imperfect; the more the cancer increases in the grade group, the better was the correlation.

Magnetic resonance imaging-transrectal ultrasound image fusion guidance of prostate biopsies: current status, challenges and future perspectives

The use of multiparametric magnetic resonance imaging (mpMRI) in prostate cancer (PCa) diagnosis is rapidly evolving to try to overcome the limitations of the current diagnostic pathway using systematic transrectal ultrasound-guided biopsies (TRUS_bx) for all men with clinical suspicion of PCa. Prostate mpMRI allows for high quality lesion detection and characterization and has been shown to improve detection of significant PCa with a more accurate Gleason score grading. Suspicious lesions can be stratified by suspicion and sampled by selective MRI-guided targeted biopsies (TBx) for improved diagnostic accuracy. Several TBx methods have been established and include MRI/TRUS image fusion biopsies (cognitive or software-assisted) and in-bore biopsies, but none have yet proven superior in clinical practice. However, while MRI in-bore biopsy is not routinely used due to its costs and limited availability, MRI/TRUS image fusion is rapidly embraced as it allows skilled urologists to perform TBx in an outpatient clinic. Furthermore, it gives the operator the advantage of adding TBx to the systematic standard biopsy scheme, which is the currently recommended approach. With the anticipated increased future use of prebiopsy mpMRI, a more widespread implementation of MRI/TRUS image fusion platforms is concurrently expected in clinical practice. Therefore, the objective of this review is to assess the current status, challenges and future perspectives of prostate MRI/TRUS image fusion biopsies.

Characterization of prostate microstructure using water diffusion and NMR relaxation

For many pathologies, early structural tissue changes occur at the cellular level, on the scale of micrometers or tens of micrometers. Magnetic resonance imaging (MRI) is a powerful non-invasive imaging tool used for medical diagnosis, but its clinical hardware is incapable of reaching the cellular length scale directly. In spite of this limitation, microscopic tissue changes in pathology can potentially be captured indirectly, from macroscopic imaging characteristics, by studying water diffusion. Here we focus on water diffusion and NMR relaxation in the human prostate, a highly heterogeneous organ at the cellular level. We present a physical picture of water diffusion and NMR relaxation in the prostate tissue, that is comprised of a densely-packed cellular compartment (composed of stroma and epithelium), and a luminal compartment with almost unrestricted water diffusion. Transverse NMR relaxation is used to identify fast and slow T ₂ components, corresponding to these tissue compartments, and to disentangle the luminal and cellular compartment contributions to the temporal evolution of the overall water diffusion coefficient. Diffusion in the luminal compartment falls into the short-time surface-to-volume (S/V) limit, indicating that only a small fraction of water molecules has time to encounter the luminal walls of healthy tissue; from the S/V ratio, the average lumen diameter averaged over three young healthy subjects is measured to be 217.7±188.7 μm. Conversely, the diffusion in the cellular compartment is highly restricted and anisotropic, consistent with the fibrous character of the stromal tissue. Diffusion transverse to these fibers is well described by the random permeable barrier model (RPBM), as confirmed by the dynamical exponent ϑ = 1/2 for approaching the long-time limit of diffusion, and the corresponding structural exponent p = -1 in histology. The RPBM-derived fiber diameter and membrane permeability were 19.8±8.1 μm and 0.044±0.045 μm/ms, respectively, in agreement with known values from tissue histology and membrane biophysics. Lastly, we revisited 38 prostate cancer cases from a recently published study, and found the same dynamical exponent ϑ = 1/2 of diffusion in tumors and benign regions. Our results suggest that a multi-parametric MRI acquisition combined with biophysical modeling may be a powerful non-invasive complement to prostate cancer grading, potentially foregoing biopsies.

A model describing diffusion in prostate cancer

PURPOSE

Quantitative diffusion MRI has frequently been studied as a means of grading prostate cancer. Interpretation of results is complicated by the nature of prostate tissue, which consists of four distinct compartments: vascular, ductal lumen, epithelium, and stroma. Current diffusion measurements are an ill-defined weighted average of these compartments. In this study, prostate diffusion is analyzed in terms of a model that takes explicit account of tissue compartmentalization, exchange effects, and the non-Gaussian behavior of tissue diffusion.

METHOD

The model assumes that exchange between the cellular (ie, stromal plus epithelial) and the vascular and ductal compartments is slow. Ductal and cellular diffusion characteristics are estimated by Monte Carlo simulation and a two-compartment exchange model, respectively. Vascular pseudodiffusion is represented by an additional signal at b = 0. Most model parameters are obtained either from published data or by comparing model predictions with the published results from 41 studies. Model prediction error is estimated using 10-fold cross-validation.

RESULTS

Agreement between model predictions and published results is good. The model satisfactorily explains the variability of ADC estimates found in the literature.

CONCLUSION

A reliable model that predicts the diffusion behavior of benign and cancerous prostate tissue of different Gleason scores has been developed. Magn Reson Med 78:316-326, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Analysis of Laterality and Percentage of Tumor Involvement in 1386 Prostatectomized Specimens for Selection of Unilateral Focal Cryotherapy

In total, 1386 paraffin embedded radical prostatectomy specimens from patients with clinically localized prostate cancer (PCa) excised between 2002–06 were analyzed. Pathologic assessment paid particular attention to laterality and percentage of tumor involvement (PTI) along with pathologic Gleason Score (pGS). Completely unilateral cancers were identified in 254 (18.3%) patients, and in 39% cases of them the signs of clinically significant PCa were revealed. The majority of unilateral tumors (72%) were low volume with a PTI of ≤5. This study suggests that only a select group of men diagnosed with PCa have completely unilateral cancers that would be amenable to focal ablation therapy targeting 1 lobe. Further study is needed to develop predictive models for those patients likely to have small, unilateral cancers that may be amenable to focal therapy.

The Quantitative Criteria Based on the Fractal Dimensions, Entropy, and Lacunarity for the Spatial Distribution of Cancer Cell Nuclei Enable Identification of Low or High Aggressive Prostate Carcinomas

Background: Tumor grading, PSA concentration, and stage determine a risk of prostate cancer patients with accuracy of about 70%. An approach based on the fractal geometrical model was proposed to eliminate subjectivity from the evaluation of tumor aggressiveness and to improve the prediction. This study was undertaken to validate classes of equivalence for the spatial distribution of cancer cell nuclei in a larger, independent set of prostate carcinomas.

Methods: The global fractal capacity D₀, information D₁ and correlation D₂ dimension, the local fractal dimension (LFD) and the local connected fractal dimension (LCFD), Shannon entropy H and lacunarity λ were measured using computer algorithms in digitalized images of both the reference set (n = 60) and the test set (n = 208) of prostate carcinomas.

Results: Prostate carcinomas were re-stratified into seven classes of equivalence. The cut-off D₀-values 1.5450, 1.5820, 1.6270, 1.6490, 1.6980, 1.7640 defined the classes from C1 to C7, respectively. The other measures but the D₁ failed to define the same classes of equivalence. The pairs (D₀, LFD), (D₀, H), (D₀, λ), (D₁, LFD), (D₁, H), (D₁, λ) characterized the spatial distribution of cancer cell nuclei in each class. The co-application of those measures enabled the subordination of prostate carcinomas to one out of three clusters associated with different tumor aggressiveness. For D₀ < 1.5820, LFD < 1.3, LCFD > 1.5, H < 0.7, and λ > 0.8, the class C1 or C2 contains low complexity low aggressive carcinomas exclusively. For D₀ > 1.6980, LFD > 1.7644, LCFD > 1.7051, H > 0.9, and λ < 0.7, the class C6 or C7 contains high complexity high aggressive carcinomas.

Conclusions: The cut-off D₀-values defining the classes of equivalence were validated in this study. The cluster analysis suggested that the number of the subjective Gleason grades and the number of the objective classes of equivalence could be decreased from seven to three without a loss of clinically relevant information. Two novel quantitative criteria based on the complexity and the diversity measures enabled the identification of low or high aggressive prostate carcinomas and should be verified in the future multicenter, randomized studies.

Clinical significance of single microscopic focus of adenocarcinoma at prostate biopsy

Objective

Prostate cancer (PC) is one of the most common cancer and an important reason of cancer specific death. The incidence of patients who diagnosed at low stage increased because of widespread using Prostate Specific Antigen (PSA) testing. We evaluated the patients who were diagnosed single microscopic focus of adenocarcinoma and treated radical prostatectomy at final pathology.

Methods

The patients who underwent transrectal ultrasound guided prostate biopsy between January 2004 and January 2012 were enrolled retrospectively. We extracted the patients who were diagnosed single microscopic focus of adenocarcinoma and treated with RP. Single microscopic adenocarcinoma was defined as one single focus measuring 3 mm or less, well differentiated (Gleason ≤6) adenocarcinoma. 37 patients were included at the study. Clinical data; including age, serum PSA levels, PSA density and prior biopsy and prostatectomy specimen results were recorded. In pathological examination; high molecular weight cytokeratin (HMW-CK), p63, and alpha-methylacyl-CoA racemase (AMACR) were used for differential diagnosis.

Results

The patients' ages were between 42 and 77 with a mean age of 64.9 ± 7.57 years. Mean PSA levels and prostate volumes were 8.03 ± 5.21 ng/ml and 54 ± 25.51 cc. T0, T2a, T2c and T3a were reported in 2 patients, 17 patients, 17 patients and 1 patient after pathological evaluation. According to the Gleason grading system; 6 patients were 7 (3 + 4), one patient was 7 (4 + 3), one patient was 5 (3 + 2) and 27 patients were 6 (3 + 3).

Conclusion

Small volume of cancer at prostate biopsy is not necessarily small cancer in radical prostatectomy. The treatment choice may be over or under treatment for some patients, so the patients must be informed when choosing the treatment.

Probability modeling of the number of positive cores in a prostate cancer biopsy session, with applications

Among men, prostate cancer (CaP) is the most common newly diagnosed cancer and the second leading cause of death from cancer. A major issue of very large scale is avoiding both over-treatment and under-treatment of CaP cases. The central challenge is deciding clinical significance or insignificance when the CaP biopsy results are positive but only marginally so. A related concern is deciding how to increase the number of biopsy cores for larger prostates. As a foundation for improved choice of number of cores and improved interpretation of biopsy results, we develop a probability model for the number of positive cores found in a biopsy, given the total number of cores, the volumes of the tumor nodules, and - very importantly - the prostate volume. Also, three applications are carried out: guidelines for the number of cores as a function of prostate volume, decision rules for insignificant versus significant CaP using number of positive cores, and, using prior distributions on total tumor size, Bayesian posterior probabilities for insignificant CaP and posterior median CaP. The model-based results have generality of application, take prostate volume into account, and provide attractive tradeoffs of specificity versus sensitivity. Copyright © 2015 John Wiley & Sons, Ltd.

On the relationship between tumor structure and complexity of the spatial distribution of cancer cell nuclei: a fractal geometrical model of prostate carcinoma

BACKGROUND

A risk of the prostate cancer patient is defined by both the objective and subjective criteria, that is, PSA concentration, Gleason score, and pTNM-stage. The subjectivity of tumor grading influences the risk assessment owing to a large inter- and intra-observer variability. Pathologists propose a central prostate pathology review as a remedy for this problem; yet, the review cannot eliminate the subjectivity from the diagnostic algorithm. The spatial distribution of cancer cell nuclei changes during tumor progression. It implies changes in complexity measured by the capacity dimension D0, the information dimension D1, and the correlation dimension D2.

METHODS

The cornerstone of the approach is a model of prostate carcinomas composed of the circular fractals CF(4), CF(6 + 0), and CF(6 + 1). This model is both geometrical and analytical, that is, its structure is well-defined, the capacity fractal dimension D0 can be calculated for the infinite circular fractals, and the dimensions D0, D1, D2 can be computed for their finite counterparts representing distribution of cell nuclei. The model enabled both the calibration of the software and the validation of the measurements in 124 prostate carcinomas. The ROC analysis defined the cut-off D0 values for seven classes of complexity.

RESULTS

The Gleason classification matched in part with the classification based on the D0 values. The mean ROC sensitivity was 81.3% and the mean ROC specificity 75.2%. Prostate carcinomas were re-stratified into seven classes of complexity according to their D0 values. This increased both the mean ROC sensitivity and the mean ROC specificity to 100%. All homogeneous Gleason patterns were subordinated to the class C1, C4, or C7. D0 = 1.5820 was the cut-off D0 value between the complexity class C2 and C3 representing low-risk cancers and intermediate-risk cancers, respectively.

CONCLUSIONS

The global fractal dimensions eliminate the subjectivity in the diagnostic algorithm of prostate cancer. Those complexity measures enable the objective subordination of carcinomas to the well-defined complexity classes, and define subgroups of carcinomas with very low malignant potential (complexity class C1) or at a large risk of progression (complexity ass C7).

Combination of clinical characteristics and transrectal ultrasound-guided biopsy to predict lobes without significant cancer: application in patient selection for hemiablative focal therapy

PURPOSE

A major limitation of performing hemiablative focal therapy (FT) for prostate cancer (PCa) is the possibility of accompanying significant cancer in the contralateral side of the prostate that is missed on prostate biopsy. We attempted to verify whether clinical and biopsy-related parameters can be used to predict the absence of significant cancer in the prostate lobe.

METHODS

We assumed that hemiablative FT could be performed in patients with low-risk PCa, with unilateral tumors as assessed by transrectal ultrasound-guided biopsy. We evaluated 214 patients who had undergone radical prostatectomy (RP) and fulfilled the eligibility criteria. Seemingly preserved lobes, defined by the absence of cancer on biopsy, were classified as lobes with no cancer (LNC), lobes with insignificant cancer (LIC), and lobes with significant cancer (LSC) according to RP pathology. Cases with an estimated tumor volume of <0.5 mL, a Gleason score of <7, and organ confinement without Gleason pattern 4 were classified as LIC. Univariate and multivariate logistic regression analyses were performed to identify predictors for LSC. Predictive accuracies of the multivariate models were assessed using receiver operating characteristic curve-derived areas under the curve.

RESULTS

Of 214 evaluated lobes, 45 (21.0%), 62, (29.0%), and 107 (50.0%) were classified as LNC, LIC, and LSC, respectively. Among the clinical and biopsy-related parameters, prostate-specific antigen density and prostate volume were identified as significant predictors for LSC in univariate regression analysis. However, multivariate analysis did not identify an independent predictor. Predictive accuracies of the multivariate models did not exceed 70.4%.

CONCLUSIONS

Conventional parameters have limited value in predicting LSC in patients who are candidates for hemiablative FT.

Identification of FISH biomarkers to detect chromosome abnormalities associated with prostate adenocarcinoma in tumour and field effect environment

Background

To reduce sampling error associated with cancer detection in prostate needle biopsies, we explored the possibility of using fluorescence in situ hybridisation (FISH) to detect chromosomal abnormalities in the histologically benign prostate tissue from patients with adenocarcinoma of prostate.

Methods

Tumour specimens from 33 radical prostatectomy (RP) cases, histologically benign tissue from 17 of the 33 RP cases, and 26 benign prostatic hyperplasia (BPH) control cases were evaluated with Locus Specific Identifier (LSI) probes MYC (8q24), LPL (8p21.22), and PTEN (10q23), as well as with centromere enumerator probes CEP8, CEP10, and CEP7. A distribution of FISH signals in the tumour and histologically benign adjacent tissue was compared to that in BPH specimens using receiver operating characteristic curve analysis.

Results

The combination of MYC gain, CEP8 Abnormal, PTEN loss or chromosome 7 aneusomy was positive in the tumour area of all of the 33 specimens from patients with adenocarcinomas, and in 88% of adjacent histologically benign regions (15 out of 17) but in only 15% (4 out of 26) of the benign prostatic hyperplasia control specimens.

Conclusions

A panel of FISH markers may allow detection of genomic abnormalities that associate with adenocarcinoma in the field adjacent to and surrounding the tumour, and thus could potentially indicate the presence of cancer in the specimen even if the cancer focus itself was missed by biopsy and histology review.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Single foci prostate cancer: current diagnosis and management

Diagnosis of small prostate cancer foci is a real challenge for pathologists and urologists as it carries the risk of false positive or negative diagnosis with clinical consequences. Diagnosis of small prostate cancer foci requires a strict methodological approach which includes a search for major and minor features under low and high magnification. Ambiguous cases can be further clarified with the use of basal cell immunomarkers complemented by a positive indicator of malignancy. Despite the new diagnostic armamentarium, a few cases will continue to remain doubtful and might require an appropriate rebiopsy.

Prostate cancer: multiparametric MRI for index lesion localization--a multiple-reader study

OBJECTIVE

The purpose of this study was to evaluate the utility of multiparametric MRI in localization of the index lesion of prostate cancer.

MATERIALS AND METHODS

Fifty-one patients who underwent 3-T MRI of the prostate with a pelvic phased-array coil that included T2-weighted, diffusion-weighted, and dynamic contrast-enhanced sequences before prostatectomy were included. Six radiologists assessed all images to identify the lesion most suspicious of being the index lesion, which was localized to one of 18 regions. A uropathologist using the same 18-region scheme reviewed the prostatectomy slides to localize the index lesion. MRI performance was assessed by requiring either an exact match or an approximate match (discrepancy of up to one region) between the MRI and pathologic findings in terms of assigned region.

RESULTS

The pathologist identified an index lesion in 49 of 51 patients. In exact-match analysis, the average sensitivity was 60.2% (range, 51.0-63.3%), and the average positive predictive value (PPV) was 65.3% (range, 61.2-69.4%). In approximate-match analysis, the average sensitivity was 75.9% (range, 65.3-69.6%), and the average PPV was 82.6% (range, 79.2-91.4%). The sensitivity was higher for index lesions with a Gleason score greater than 6 in exact-match (74.8% vs 15.3%, p<0.001) and approximate-match (88.7% vs 36.1%, p=<0.001) analyses and for index lesions measuring at least 1 cm in approximate-match analysis (80.3% vs 58.3%, p=0.016). In exact-match analysis, 30.0%, 44.9%, and 79.1% of abnormalities found with one, two, and three MRI parameters represented the index lesion (p<0.001).

CONCLUSION

The sensitivity and PPV of multiparametric MRI for index lesion localization were moderate, although they improved in the setting of more aggressive pathologic features and a greater number of abnormal MRI parameters, respectively.

Minimal or No Residual Prostatic Adenocarcinoma on Radical Prostatectomy: A 5-Year Experience With “Vanishing Carcinoma Phenomenon”

Context.—“Vanishing carcinoma phenomenon” (VC) has been defined as the finding of minute or no cancer on radical prostatectomy specimens after a positive biopsy.

Objective.—To discuss our experience with VC and to recommend guidelines for its detection.

Design.—One thousand seven hundred forty-one radical prostatectomy specimens (2004–2009) processed by whole-mount section procedure yielded 21 (1.2%) cases with VC and 6 (0.34%) cases with minimal carcinoma (≤2 mm) in the radical prostatectomy specimen. To find the eluding carcinoma in VC cases or more carcinoma in minimal carcinoma cases, the following was done: 3 levels of all the paraffin blocks were obtained; if negative, the paraffin blocks were melted, the tissue was flipped, and 3 levels were prepared. The tumor bank frozen tissue was also processed for routine examination.

Results.—Three deeper levels in the radical prostatectomy specimen of 21 VC cases failed to show malignancy; however, the flipping and recutting of the tissue yielded a focus of carcinoma (1–5 mm) in 16 of 21 cases and in 3 of 16 cases in the saved frozen tissue. In 1 of the 6 cases with minimal carcinoma, subsequent recuts of the flipped tissue displayed carcinoma (2 foci of tumor, &lt;1 mm each).

Conclusions.—In VC we recommend: embed and process any remaining prostatic tissue including any saved fresh-frozen tissue; obtain 3 levels of each paraffin block; if results are negative, melt and flip the tissue and obtain 3 more levels. Following the above guidelines, a hidden carcinoma may be detected in the majority of the cases of VC.

The 20-core prostate biopsy as an initial strategy: impact on the detection of prostatic cancer

INTRODUCTION

To increase the detection rate of prostate cancer in recent years, we examined the increase in the number of cores taken at initial prostate biopsy. We hypothesized that an increasing number of cores may undermine the accuracy of models predicting the presence of prostate cancer at initial biopsy in patients submitted to 20-core initial biopsy.

METHODS

A total of 232 consecutive patients with prostate-specific antigen (PSA) between 4 and 20 ng/mL and/or abnormal digital rectal examination (DRE) underwent 12-core prostate biopsy protocol (group 1) or 20-core prostate biopsy protocol (group 2). The patients were divided into subgroups according to the results of their serum PSA and prostate volume. We evaluated the cancer detection rate overall and in each subgroup. Clinical data were analyzed using chi-square analysis and the unpaired t-test or 1-way ANOVA with significance considered at 0.05.

RESULTS

The 2 groups of patients were not significantly different with regard to parameters (age, abnormal DRE and serum PSA), although median prostate volume in group 1 (57.76 +/- 26.94 cc) were slighter greater than in group 2. Cancer detection rate for patients submitted to 20 prostate biopsy was higher than patients submitted to 12 prostate biopsy (35.2% vs. 25%, p = 0.095). Breakdown to PSA level showed a benefit to 20 prostate biopsy for PSA <6 ng/mL (37.1% vs. 12.9%, p = 0.005). Stratifying results by prostate volume, we found that the improvement of cancer detection rate with 20 prostate biopsy was significant in patients with a prostate volume greater than 60 cc (55% in 20 prostate biopsy vs. 11.3% p < 0.05). Morbidity rates were identical in groups 1 and 2 with no statistically significant difference. There appeared to be no greater risk of infection and bleeding with 20 prostate biopsy protocol.

CONCLUSION

The 20-core biopsy protocol was more efficient than the 12-core biopsy protocol, especially in patients with prostate specific antigen <6 ng/mL and prostate volume greater than 60 cc.

Role of magnetic resonance imaging before initial biopsy: comparison of magnetic resonance imaging-targeted and systematic biopsy for significant prostate cancer detection

OBJECTIVE

•To compare magnetic resonance imaging (MRI)-targeted biopsies with extended systematic biopsies for the detection of significant prostate cancer.

METHODS

•In all, 555 consecutive patients with suspicion of prostate cancer had pre-biopsy dynamic contrast-enhanced 1.5-tesla (T) MRI with pelvic coil, 10-12 transrectal ultrasound-guided extended systematic biopsies plus two targeted biopsies at any MRI area suspicious for malignancy. •Significant prostate cancer was defined as >5 mm total cancer length and/or any Gleason pattern >3. •Cancer length and grade at biopsy were reported and located on a 24-sector map.

RESULTS

•Median (range) prostate-specific antigen (PSA) was 6.75 (0.18-100) ng/mL. •MRI was positive in 351 (63%) patients and, overall, 302 (54%) had cancer at extended systematic biopsies and/or targeted biopsies. Of 302 cancers detected, 249 (82%) were significant prostate cancers and 53 (18%) were nonsignificant prostate cancers. •Extended systematic biopsies did not detect 12 significant prostate cancers and targeted biopsies did not detect 13 significant prostate cancers. For significant prostate cancer detection, sensitivity, specificity and accuracy of targeted biopsies were 0.95, 1.0 and 0.98. The values for extended systematic biopsies were 0.95, 0.83, and 0.88. •The detection accuracy of significant prostate cancer by targeted biopsies was higher than that by extended systematic biopsies (P < 0.001). Targeted biopsies also detected 16% more grade 4/5 cases and better quantified the cancer than extended systematic biopsies, with cancer length of 5.56 vs. 4.70 mm (P= 0.002). • A targeted biopsies-only strategy without extended systematic biopsies would have necessitated a mean of 3.8 cores performed in only 63% of patients with positive MRI and avoided the potentially unnecessary diagnosis of 13% (53/302) of nonsignificant prostate cancers.

CONCLUSIONS

• Strategy of targeted biopsies alone at pre-biopsy MRI-suspicious areas is an attractive potential alternative to extended systematic biopsies for detection of significant prostate cancer. •Further studies are necessary to validate the strategy of targeted biopsies alone.

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.

The role of transrectal saturation biopsy in tumour localization: pathological correlation after retropubic radical prostatectomy and implication for focal ablative therapy

OBJECTIVE

• To evaluate the accuracy of an initial 24-core prostate biopsy scheme (PBx24) in predicting unilateral prostate cancer (PCa) in radical prostatectomy (RP) specimens.

PATIENTS AND METHODS

• Between 2005 and 2008, 203 consecutive patients underwent PBx24 followed by RP for PCa. The area under the curve (AUC) was used to evaluate the accuracy of unilateral PCa on PBx24 to predict unilateral PCa in RP specimens. • The positive predictive value (PPV) and negative predictive value (NPV) were also calculated. Moreover, in patients with unilateral PCa on biopsy, univariable and multivariable logistic regression analyses tested the relationship between the presence of unilateral PCa in an RP specimen and the variables: age, prostate-specific antigen (PSA), total prostate volume, clinical stage, primary Gleason grade, secondary Gleason grade and the number of positive cores.

RESULTS

• PCa cores were unilateral in 115 patients (56.7%) on biopsy. Of those, only 26 (22.6%) had unilateral PCa in the RP specimen (AUC, 72.9%; PPV, 22.6%; NPV, 98.8%). In patients with clinically low-risk tumours, only 17 of 63 (27%) had a unilateral PCa on PBx24 and in the RP specimen (AUC, 59.1%; PPV, 27.0%; NPV, 100.0%). • None of the examined variables was an independent predictor of the presence of unilateral PCa in the RP specimen (all P > 0.05).

CONCLUSIONS

• Initial PBx24 is not sufficiently accurate to be dependable as a method of predicting tumour laterality in RP specimens. Therefore, the use of PBx24 to guide hemi-ablation therapy of PCa may lead to mistreatment in a considerable proportion of patients. • Moreover, none of the routinely available clinical and pathological characteristics appears to improve the ability of unilateral PCa on biopsy to predict unilateral PCa in the RP specimen.

Single positive core prostate cancer in a 12-core transrectal biopsy scheme: clinicopathological implications compared with multifocal counterpart

Purpose

The incidence of single positive core prostate cancer at the time of biopsy appears to be increasing in the prostate-specific antigen (PSA) era. To determine the clinical implication of this disease, we analyzed surgical and pathological characteristics in comparison with multiple positive core disease.

Materials and Methods

Among 108 consecutive patients who underwent robotic radical prostatectomy following a diagnosis of prostate cancer based on a 12-core transrectal biopsy performed by the same method in a single institute, outcomes from 26 patients (Group 1) diagnosed on the basis of a single positive biopsy core and from 82 patients (Group 2) with multiple positive biopsy cores were analyzed.

Results

The preoperative PSA value, Gleason score, prostate volume, and D'Amico's risk classification of each group were similar. The proportion of intermediate+highrisk patients was 69.2% in Group 1 and 77.9% in Group 2 (p=0.22). Total operative time and blood loss were similar. Based on prostatectomy specimens, only 3 patients (11.5%) in Group 1 met the criteria for an indolent tumor (7.31% in Group 2). Although similarities were observed during preoperative clinical staging (p=0.13), the final pathologic stage was significantly higher in Group 2 (p=0.001). The positive-margin rate was also higher in Group 2 (11.5% vs. 31.7%, p=0.043). Despite similarity in upstaging after prostatectomy in each group (p=0.86), upgrading occurred more frequently in Group 1 (p=0.014, 42.5% vs. 19.5%). No clinical parameters were valuable in predicting upgrading.

Conclusions

Most single positive core prostate cancer diagnoses in 12-core biopsy were clinically significant with similar risk stratification to multiple positive core prostate cancers. Although the positive-margin rate was lower than in multiple positive core disease, an increase in Gleason score after radical prostatectomy occurred more frequently.

Differential gene expression in benign prostate epithelium of men with and without prostate cancer: evidence for a prostate cancer field effect

BACKGROUND

Several malignancies are known to exhibit a "field effect," whereby regions beyond tumor boundaries harbor histologic or molecular changes that are associated with cancer. We sought to determine if histologically benign prostate epithelium collected from men with prostate cancer exhibits features indicative of premalignancy or field effect.

EXPERIMENTAL DESIGN

Prostate needle biopsies from 15 men with high-grade (Gleason 8-10) prostate cancer and 15 age- and body mass index-matched controls were identified from a biospecimen repository. Benign epithelia from each patient were isolated by laser capture microdissection. RNA was isolated, amplified, and used for microarray hybridization. Quantitative PCR was used to determine the expression of specific genes of interest. Alterations in protein expression were analyzed through immunohistochemistry.

RESULTS

Overall patterns of gene expression in microdissected benign prostate-associated benign epithelium (BABE) and cancer-associated benign epithelium (CABE) were similar. Two genes previously associated with prostate cancer, PSMA and SSTR1, were significantly upregulated in the CABE group (false discovery rate <1%). Expression of other prostate cancer-associated genes, including ERG, HOXC4, HOXC5, and MME, were also increased in CABE by quantitative reverse transcription-PCR, although other genes commonly altered in prostate cancer were not different between the BABE and CABE samples. The expression of MME and PSMA proteins on immunohistochemistry coincided with their mRNA alterations.

CONCLUSION

Gene expression profiles between benign epithelia of patients with and without prostate cancer are very similar. However, these tissues exhibit differences in the expression levels of several genes previously associated with prostate cancer development or progression. These differences may comprise a field effect and represent early events in carcinogenesis.

Pathological findings at radical prostatectomy in Japanese prospective active surveillance cohort

OBJECTIVES

The present study was carried out to analyze pathological features of prostatectomy specimens performed at different timing and trigger during active surveillance.

METHODS

One hundred and thirty-four patients that fit a selection condition similar to the so-called Hopkins' criteria were enrolled into the present study between January 2002 and December 2003. Patients were recommended to start curable treatment when they showed prostate-specific antigen-doubling time of 2 years or shorter or pathological progression at 1-year re-biopsy. Median observation period was 61 months.

RESULTS

Fourteen patients underwent radical prostatectomy immediately after enrollment (Group A) whereas 28 patients underwent radical prostatectomy after substantial periods of active surveillance (Group B). Of the 28 Group B, trigger of radical prostatectomy was on protocol in 17 patients (Group B1) whereas 11 patients underwent radical prostatectomy by their preference (Group B2). Upgrade from initial biopsy was observed in 43% of Group A and 68% of Group B. Upgrade was more frequently observed in Group B1 than B2 with border line significance (P = 0.075). Perineural infiltration and positive surgical margin rates of Group B1 were significantly higher than those of B2 (P < 0.05).

CONCLUSIONS

Unfavorable pathological features of surgical specimens were more frequently observed in patients who underwent radical prostatectomy due to short prostate-specific antigen-doubling time or biopsy findings than those who underwent radical prostatectomy because of other reasons including patients' preference. Rates of unfavorable pathological features at radical prostatectomy that deviate initial selection criteria was high enough to support integration of frequent biopsies into active surveillance program.

Can the conventional sextant prostate biopsy accurately predict unilateral prostate cancer in low-risk, localized, prostate cancer?

We evaluate the reliability of routine sextant prostate biopsy to detect unilateral lesions. A total of 365 men with complete records including all clinical and pathologic variables who underwent a preoperative sextant biopsy and subsequent radical prostatectomy (RP) for clinically localized prostate cancer at our medical center between January 1996 and December 2006 were identified. When the sextant biopsy detects unilateral disease, according to RP results, the NPV is high (91%) with a low false negative rate (9%). However, the sextant biopsy has a PPV of 28% with a high false positive rate (72%). Therefore, a routine sextant prostate biopsy cannot provide reliable, accurate information about the unilaterality of tumor lesion(s).

Prostate cancer: the new landscape

PURPOSE OF REVIEW

This review highlights current features of the changing landscape of the US population with newly diagnosed prostate cancer and discusses new treatment options utilizing noninvasive or minimally invasive management.

RECENT FINDINGS

Recent evidence of significant changes in the current prostate cancer landscape is based on clinical data and pathological specimens after radical prostatectomy that suggest a further increase of the low-risk patient population that may require reconsideration of treatment options. For a select cohort of patients with low-risk features, based on the D'Amico definition, active surveillance or focal ablative therapy may be a rational alternative to surgical prostatectomy or whole-gland radiation therapy that still dominate as the main treatment approaches for localized prostate cancer.

SUMMARY

As the prostate-specific antigen era continues to mature, we continue to witness stage migration. A growing segment of the localized prostate cancer patient population has very low-volume, low-grade disease. Although active surveillance may be an appropriate approach for a selected group of patients, the progression requiring whole-gland therapy remains a challenge. Organ-sparing focal therapy might ideally fill the gap between a surveillance strategy and whole-gland treatment providing a reasonable balance between cancer control and quality of life.

Utility of a 3-Dimensional Transrectal Ultrasound-guided Prostate Biopsy System for Prostate Cancer Detection

The 3-D transrectal ultrasound (TRUS)-guided prostate biopsy system is a novel device that allows precise needle placement in a template fashion. We evaluate its utility for prostate cancer (PCa) detection. A retrospective analysis was performed evaluating 68 prospective patients at the Duke Prostate Center who underwent a prostate biopsy using a 3-D TRUS-guided system. After creation of a three-dimensional map of the prostate, a computer algorithm identified an ideal biopsy scheme based on the measured dimensions of the prostate. The system then used a fixed template that allowed prostate biopsy at specific locations with the ability to target the same region of the prostate in the future if needed. For all patients, a 12-core biopsy pattern was used to cover medial and lateral areas of the base, mid-gland, and apex. In total, 68 patients underwent 3-D TRUS-guided prostate biopsies between April 2006 and November 2007 for prostate cancer detection. The indication for prostate biopsy was PSA ≥ 4.0 ng/ml in 47 (69%) patients, abnormal digital rectal examination (DRE) in 17 (25%), and atypia on previous biopsy in 4 (6%) patients. Prostate cancer was detected in 18 patients (26.5%) and 7 (10.3%) had atypical small acinar proliferation (ASAP). The highest frequency (55.5%) from all cases of cancer detected was identified when 3-D TRUS biopsy was used as the initial biopsy. This study demonstrates that a 3-D TRUS-guided biopsy system translates to a more frequent detection of prostate cancer among patients undergoing an initial prostate biopsy than a subsequent one. More comprehensive studies are warranted to corroborate and extend the results of this study.

Utility of extended pattern prostate biopsies for tumor localization: pathologic correlations after radical prostatectomy

BACKGROUND

Focal targeted therapy has been proposed as a potential treatment for localized prostate cancer in an attempt to reduce morbidity. However, these modalities rely heavily on accurate tumor localization to achieve total tumor ablation. In the current study, we sought to examine the ability of contemporary extended pattern prostate biopsy to predict the location of tumors.

METHODS

A total of 281 men with prostate cancer detected via a standardized extended pattern biopsy template with at least 12 cores and who subsequently underwent radical prostatectomy were evaluated. Tumor location on biopsy, stratified by laterality and by site (apex vs mid-base prostate), was compared with corresponding locations on the prostatectomy specimen. Generalized estimating equation models were developed to assess the effects of clinical variables on pathologic agreement between biopsy and prostatectomy specimens.

RESULTS

Of the 281 prostate biopsies, the positive predictive value (PPV) of right and left needle biopsy was high at 97.3% and 96.7%, respectively. However, the negative predictive value (NPV) was low at 24.7% and 31.3%, respectively. When more specific locations were considered, the NPV improved at the apex. However, this came at a cost to the PPV. Tumor focality on prostatectomy specimen was the only clinical feature found to be significantly and consistently related to pathologic agreement.

CONCLUSIONS

Contemporary extended pattern prostate biopsy, although able to diagnose cancers, fails to provide reliable localization of tumors to specific areas of the prostate. Focal therapy, which relies heavily on localization, should only be performed with this caveat in mind.

Diagnostic accuracy of extended biopsies for the staging of microfocal prostate cancers in autopsy specimen

Clinically insignificant prostate cancers may be predicted when biopsies show a microfocal cancer (MiFC). However, at least one-third of MiFC are underestimated by biopsies. The aim of this study was to evaluate the staging accuracy of different biopsy regimen showing a MiFC. We performed 18 biopsy cores on 164 autopsy prostates. Six cores were taken from the mid-peripheral zone (MPZ), 6 from the lateral PZ (LPZ) and 6 from the central zone (CZ). We tested seven different biopsy regimens by distinguishing the MPZ, LPZ or CZ biopsies either separately or associated with each other. Of the cancers detected by biopsies, we selected those showing a MiFC and compared our findings with whole mount analysis. The positive predictive value of a MiFC referred to how often, when needle biopsies showed a MiFC, there was a clinically insignificant cancer on whole mount prostate analysis. We found that the positive predictive value of a MiFC on 6 or 12 biopsy cores was similar irrespective of biopsy location (P approximately 1). On MPZ, MPZ plus LPZ and all 18 biopsies, it was 40, 70 and 87%, respectively (P<0.1). Tumor volume of cancers showing a MiFC on MPZ biopsies was significantly higher than those showing a MiFC on MPZ plus LPZ, or all 18 biopsies (P<0.05). These results show that performing additional cores in case of MiFC on sextant biopsies may help differentiating significant from insignificant cancers.

[Insignificant prostate cancer. Analysis our series]

The objective of this study is to analyse the specimen of radical prostatectomy of patients who had, prior to the surgery insignificant prostate cancer biopsies. The end point is demonstrate the possibility of an active surveillance as a therapeutic option for prostate cancer in selected is the possibility of an active surveillance as therapeutic for the prostate cancer, in selected individuals if we are able to find diagnostic algorisms to predict the real insignificant tumours. The selected group of patients for the study has a PSA less or equal 10, one positive core of prostatic transrectal ultrasound biopsy with a Gleason score less than 7. This group of patients is considerate as having a potential insignificant tumour. We will consider prostatectomy's specimens and the Gleason sore is less than 7 and the tumoral volume is les or equal to 5%. Of 394 patients with prostate cancer and homogeneous criterias for our study, we have selected 53 patients according to the criteria of insignificant tumour in the biopsy. Our results showed that only 22 of 53 (41.5%) patients were identified as having an insignificant prostate cancer in the RP specimens. Moreover 92.2% of this tumours were organ-confined. In conclusion we are able to say that tumours of low-risk and low tumoral volume in the biopsy, do not correlate always to insignificant tumours in PR specimens, but we have observed that the majority are organ-confined tumours. Finally, the diagnostic's algorisms dies not to predict tumours that may safely treated with active monitoring.

Assessment of pathological prostate cancer characteristics in men with favorable biopsy features on predominantly sextant biopsy

BACKGROUND

The rate of insignificant prostate cancer (IPCa) is increasing.

OBJECTIVES

To examine three end points in patients with a single, positive core and no high-grade prostate cancer (PCa) at biopsy, namely (1) rate of clinical IPCa at radical prostatectomy (RP), defined as organ-confined PCa with a Gleason score of 6 or lower and tumor volume<0.5 cc; (2) rate of pathologically unfavorable PCa at RP (Gleason 7-10 or non-organ-confined disease); and (3) ability to predict either insignificant or unfavorable PCa at RP.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective analysis of 209 men with one positive biopsy core showing Gleason 6 or lower.

MEASUREMENTS

: Detailed clinical and RP data were used in multivariable logistic regression models. Their bias-corrected accuracy estimates were quantified using the area under the curve (AUC) method.

RESULTS AND LIMITATIONS

At RP, IPCa was present in 28 patients (13.4%) and pathologically unfavorable PCa, defined as Gleason 7 or higher or non-organ-confined PCa, was reported in 70 (33.5%) of 209 men; when Gleason 8 or higher or non-organ-confined PCa was considered, the proportion fell to 11%. Our multivariable models predicting different categories of pathologically unfavorable PCa at RP had an accuracy rate between 56% and 68% for predicting IPCa at RP versus 65.1% to 66.1% and 61.7% for the IPCa nomograms of Kattan et al and Nakanishi et al, respectively. Our data are not applicable to screening because they originate from a referral population.

CONCLUSIONS

Despite highly favorable biopsy features, between 11% and 33% of men had unfavorable PCa at RP and only a minority (13.4%) had pathologically confirmed IPCa. Neither clinically insignificant nor pathologically unfavorable features could be predicted with sufficient accuracy for clinical decision making.

WITHDRAWN: Can the conventional sextant prostate biopsy reliably diagnose unilateral prostate cancer in low-risk, localized, prostate cancer?

The authors hereby retract the e-publication dated 13 May 2008 and entitled, 'Can the conventional sextant prostate biopsy reliably diagnose unilateral prostate cancer in low-risk, localized, prostate cancer?' The authors are submitting a revised version with the same title. This article's statistics were performed for predicting bilateral prostate cancer outcomes. The article was written to help predict unilateral prostate cancer. Although the statistical numbers are correct, they are backwards. We apologize that the statistics indicate a contrary outcome (eg predicting bilateral cancer instead of unilateral disease).

The clinical management of patients with a small volume of prostatic cancer on biopsy: what are the risks of progression? A systematic review and meta-analysis

Clinically localized prostate cancer is associated with a wide variation in biologic behavior, and men with the less aggressive form of the disease may never develop symptoms. There has been a rise in prostate cancer incidence in countries in which the blood test for prostatic-specific antigen (PSA) is common, and concerns have been expressed that this may be because of the increased detection of indolent disease, subjecting these men to unnecessary treatment and associated side effects. For the current review, the authors conducted a systematic evaluation of the literature regarding the outcomes of men who were diagnosed on the basis of a small volume of cancer in prostatic biopsies. The results indicated that, despite differences in study design and reporting, a significant proportion of patients with microfocal cancer, regardless of how it was defined, had adverse pathologic findings and a significant risk of PSA recurrence after undergoing radical prostatectomy. Biochemical and clinical recurrences also were observed after radiotherapy or watchful waiting. The authors concluded that patients with microfocal carcinoma on biopsy should be advised that their disease is not necessarily "insignificant" and should be counseled accordingly.