Alexander Haese

Circulating miRNAs are correlated with tumor progression in prostate cancer

Circulating miRNAs have recently been indicated as practicable and promising biomarkers for noninvasive diagnosis in various tumor entities. However, cell‐free miRNAs have not been found to correlate with clinicopathological variables in epithelial carcinomas. To learn more about the potential clinical relevance of circulating miRNAs in prostate cancer, we screened 667 miRNAs in serum samples from patients with metastatic (n = 7) and localized prostate cancer (n = 14). Various miRNAs were highly abundant in the sera of patients with metastatic disease, and five upregulated miRNAs (miRNA‐375, miRNA‐9*, miRNA‐141, miRNA‐200b and miRNA‐516a‐3p) were selected for further validation. In the first validation study (n = 45), selected miRNAs were analyzed in a prospectively collected serum set taken from different prostate cancer risk groups. Most of the selected miRNAs were significantly correlated with adverse risk factors when different clinicopathological variables were analyzed. Circulating miRNA‐375 and miRNA‐141 turned out to be the most pronounced markers for high‐risk tumors. Their levels also correlated with high Gleason score or lymph‐node positive status in a second independent validation study (n = 71). In addition, the expression levels of miRNA‐375 and miRNA‐141 were monitored in 72 prostate tissue samples (36 tumor vs. 36 benign). Both miRNAs were highly expressed in all samples and significantly upregulated in the tumors compared to normal tissues. Overall, our observations suggest that miRNA‐375 and miRNA‐141 expression is enhanced in prostate cancer specimens and their release into the blood is further associated with advanced cancer disease.

Prostate Cancer Gene 3 (PCA3): Development and Internal Validation of a Novel Biopsy Nomogram

BACKGROUND Urinary prostate cancer gene 3 (PCA3) represents a promising novel marker of prostate cancer detection. OBJECTIVE To test whether urinary PCA3 assay improves prostate cancer (PCa) risk assessment and to construct a decision-making aid in a multi-institutional cohort with pre-prostate biopsy data. DESIGN, SETTING, AND PARTICIPANTS PCA3 assay cut-off threshold analyses were followed by logistic regression models which used established predictors to assess PCa-risk at biopsy in a large multi-institutional data set of 809 men at risk of harboring PCa. MEASUREMENTS Regression coefficients were used to construct four sets of nomograms. Predictive accuracy (PA) estimates of biopsy outcome predictions were quantified using the area under the curve of the receiver operator characteristic analysis in models with and without PCA3. Bootstrap resamples were used for internal validation and to reduce overfit bias. The extent of overestimation or underestimation of the observed PCa rate at biopsy was explored graphically using nonparametric loss-calibration plots. Differences in PA were tested using the Mantel-Haenszel test. Finally, nomogram-derived probability cut-offs were tested to assess the ability to identify patients with or without PCa. RESULTS AND LIMITATIONS PCA3 was identified as a statistically independent risk factor of PCa at biopsy. Addition of a PCA3 assay improved bootstrap-corrected multivariate PA of the base model between 2% and 5%. The highest increment in PA resulted from a PCA3 assay cut-off threshold of 17, where a 5% gain in PA (from 0.68 to 0.73, p=0.04) was recorded. Nomogram probability-derived risk cut-off analyses further corroborate the superiority of the PCA3 nomogram over the base model. CONCLUSIONS PCA3 fulfills the criteria for a novel marker capable of increasing PA of multivariate biopsy models. This novel PCA3-based nomogram better identifies men at risk of harboring PCa and assists in deciding whether further evaluation is necessary.

Clinical significance of p53 alterations in surgically treated prostate cancers

Despite the high number of previous studies, the role of p53 alterations in prostate cancer is not clearly defined. To address the role of p53 alterations in prostate cancer biology, a total of 2514 cancers treated by radical prostatectomy were successfully analyzed by immunohistochemistry in a tissue microarray format. Overall a low rate of p53-positive tumors was found (2.5%). A significant underestimation of p53-positive cases was excluded by subsequent large section analyses and direct sequencing of the p53 gene in subsets of our patients. Large section analysis of 23 cases considered negative on the tissue microarray yielded only one weakly p53-positive tumor. Only 4 out of 64 (6.4%) high-grade tumors, that were considered negative for p53 by immunohistochemistry, presented exon 5–8 mutations. These data suggest a high sensitivity of our immunohistochemistry approach and confirm the overall low frequency of p53 alterations in clinically localized prostate cancer. A positive p53 immunostaining was strongly associated with presence of exon 5–8 mutations (P<0.0001), advanced pT-stage (P<0.0001), high Gleason grade (P<0.0001), positive surgical margins (P=0.03) and early biochemical tumor recurrence (P<0.0001). A higher rate of positive p53 immunostaining was detected in late-stage diseases including metastatic prostate cancer (P=0.0152) and hormone-refractory tumors (P=0.0003). Moreover, p53 expression was identified as an independent predictor of biochemical tumor recurrence in the subgroup of low- and intermediate-grade cancers. In summary, the results of this study show that p53 mutations characterize a small biologically aggressive subgroup of prostate cancers with a high risk of progression after prostatectomy. The rate of p53 alterations increases with prostate cancer progression.

Validation of a Nomogram for Prediction of Side Specific Extracapsular Extension at Radical Prostatectomy

PURPOSE We have previously have reported a tree structured regression model for predicting SS-ECE. Others recently reported a logistic regression based SS-ECE nomogram. We developed a nomogram and compared the performance and discriminant properties of the tree regression and the nomogram in a contemporary cohort of European patients treated with radical retropubic prostatectomy. MATERIALS AND METHODS The cohort consisted of 1,118 patients with pretreatment prostate specific antigen 0.1 to 73.2 ng/ml (median 6.6). Each of the 2,236 prostate lobes was considered separately. Clinical stage, pretreatment PSA, biopsy Gleason sum, percent positive cores and percent cancer in the biopsy specimen were used as predictors in a logistic regression model predicting SS-ECE. Regression coefficients were then used to generate an SS-ECE nomogram. Performance characteristics and discriminant properties of the previously published tree regression were also tested in the same cohort. For internal validation and to decrease overfit bias 200 bootstrap re-samples were applied to accuracy estimates for each method. RESULTS ECE was present in 303 of 1,118 radical retropubic prostatectomy specimens (27%) and in 385 lobes (17%). In logistic regression models all variables were statistically significant multivariate predictors of SS-ECE except the percent of positive biopsy cores (p = 0.7). Bootstrap corrected predictive accuracy of the SS-ECE nomogram was 0.840 vs 0.700 for the tree regression model. CONCLUSIONS Logistic regression based nomogram predictions of SS-ECE are highly accurate and represent a valuable aid for assessing the risk of ECE prior to surgery.

A VALIDATED STRATEGY FOR SIDE SPECIFIC PREDICTION OF ORGAN CONFINED PROSTATE CANCER: A TOOL TO SELECT FOR NERVE SPARING RADICAL PROSTATECTOMY

PURPOSE Nerve sparing radical prostatectomy for prostate cancer should be restricted to patients who harbor tumors without capsular penetration. To our knowledge the selection criteria for nerve sparing radical prostatectomy are not clearly defined. We investigated a panel of preoperative tumor characteristics with respect to their ability to predict organ confined tumor growth for each lobe of the prostate to indicate unilateral or bilateral nerve sparing radical prostatectomy. MATERIALS AND METHODS Nine preoperative tumor characteristics in 278 patients with clinically localized prostate cancer were included in retrospective univariate and multivariate tree structured regression analysis. The association of clinical stage, serum prostate specific antigen (PSA), PSA density, and results of transrectal ultrasound and systematic sextant biopsy, including a quantitative assessment of cancer in the biopsies with organ confined tumor growth, was statistically evaluated. Except for serum PSA and PSA density preoperative characteristics were considered separately for each prostate lobe. Multivariate analysis results were validated prospectively in 353 patients. RESULTS On univariate analysis the number of positive biopsies was the most useful single parameter with a positive predictive value of 83% in 274 lobes and a negative predictive value of 55%, followed by mm. of tumor in the biopsy. Of all characteristics included in multivariate analysis only the number of biopsies with high grade cancer, the number of positive biopsies and serum PSA were independent for predicting organ confined cancer. When PSA was less than 10 ng./ml. and not more than 1 biopsy with high grade cancer was identified in a lobe, organ confined tumor growth was present in 86.1% of cases. On prospective validation the same criteria led to an 88.5% incidence of organ confined prostate cancer. Pooling the 2 most favorable groups led to 391 prostate lobes (70.8% of those investigated) with a positive predictive value of 82.1% (95% confidence interval 77.9% to 85.8%). Using the multivariate approach more prostate lobes were assigned to a favorable risk group than on univariate analysis. Clinical stage and simple Gleason grade did not contribute independent information for predicting organ confined disease. CONCLUSIONS Quantifying cancer and high grade cancer by systematic biopsy and serum PSA concentration are useful preoperative characteristics for predicting organ confined prostate cancer. Side specific analysis of these parameters is a flexible and reliable tool for selecting patients for nerve sparing radical prostatectomy.

Serum Isoform [−2]proPSA Derivatives Significantly Improve Prediction of Prostate Cancer at Initial Biopsy in a Total PSA Range of 2–10 ng/ml: A Multicentric European Study

BACKGROUND Strategies to reduce prostate-specific antigen (PSA)-driven prostate cancer (PCa) overdiagnosis and overtreatment seem to be necessary. OBJECTIVE To test the accuracy of serum isoform [-2]proPSA (p2PSA) and its derivatives, percentage of p2PSA to free PSA (fPSA; %p2PSA) and the Prostate Health Index (PHI)-called index tests-in discriminating between patients with and without PCa. DESIGN, SETTING, AND PARTICIPANTS This was an observational, prospective cohort study of patients from five European urologic centers with a total PSA (tPSA) range of 2-10 ng/ml who were subjected to initial prostate biopsy for suspected PCa. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS The primary end point was to evaluate the specificity, sensitivity, and diagnostic accuracy of index tests in determining the presence of PCa at prostate biopsy in comparison to tPSA, fPSA, and percentage of fPSA to tPSA (%fPSA) (standard tests) and the number of prostate biopsies that could be spared using these tests. Multivariable logistic regression models were complemented by predictive accuracy analysis and decision curve analysis. RESULTS AND LIMITATIONS Of >646 patients, PCa was diagnosed in 264 (40.1%). Median tPSA (5.7 vs 5.8 ng/ml; p=0.942) and p2PSA (15.0 vs 14.7 pg/ml) did not differ between groups; conversely, median fPSA (0.7 vs 1 ng/ml; p<0.001), %fPSA (0.14 vs 0.17; p<0.001), %p2PSA (2.1 vs 1.6; p<0.001), and PHI (48.2 vs 38; p<0.001) did differ significantly between men with and without PCa. In multivariable logistic regression models, p2PSA, %p2PSA, and PHI significantly increased the accuracy of the base multivariable model by 6.4%, 5.6%, and 6.4%, respectively (all p<0.001). At a PHI cut-off of 27.6, a total of 100 (15.5%) biopsies could have been avoided. The main limitation is that cases were selected on the basis of their initial tPSA values. CONCLUSIONS In patients with a tPSA range of 2-10 ng/ml, %p2PSA and PHI are the strongest predictors of PCa at initial biopsy and are significantly more accurate than tPSA and %fPSA.

Clinical Significance of Epidermal Growth Factor Receptor Protein Overexpression and Gene Copy Number Gains in Prostate Cancer

Purpose: The epidermal growth factor receptor (EGFR) is a protein involved in the tumor progression of many cancer types and is an important therapeutic target. To determine its role in prostate cancer, we analyzed 2,497 prostate cancers on the DNA and protein level. Experimental Design: Tissue samples from each tumor were brought into a tissue microarray and analyzed by immunohistochemistry and fluorescence in situ hybridization. A subset of cancers was also sequenced for EGFR exon 18 to 21 mutations. Results: Detectable EGFR expression was found in 18% of cancers and was significantly associated with high grade, advanced stage, and high risk for prostate-specific antigen recurrence in univariate analysis (P < 0.0001, each). Fluorescence in situ hybridization analysis with a dual-labeling probe for centromere 7 and EGFR showed increased EGFR copy number in 3.3% of cases. EGFR copy number gains were mostly due to an overrepresentation of the entire chromosome and were associated with EGFR protein expression (P < 0.0001), high grade (P < 0.0001), and advanced stage (P = 0.0056). Only one cancer had a high-level amplification (>20 EGFR gene copies per cell). This amplification was heterogeneous, involving only ∼30% of the cancer volume. EGFR mutations were not found in 35 of the cases analyzed. Conclusion: Increased EGFR expression is often seen in prostate cancer and is associated with poor prognosis. The significant association of EGFR copy number gains with protein expression argues for the significant role of minimal gene copy number changes for protein expression. Although EGFR expression was not an independent prognostic variable, the potential utility of anti-EGFR medications might be worth further investigation in EGFR-expressing prostate cancer.

Patient-reported Sexual Function After Nerve-sparing Radical Retropubic Prostatectomy

OBJECTIVE Improved selection criteria have lead to an increasing number of nerve-sparing radical retropubic prostatectomies (RRP) in patients with clinically localised prostate cancer (PCA). Patient questionnaire based outcome analysis on post-operative erectile function after uni- or bilateral nerve-sparing RRP is described. METHODS Between January 1992 and March 1999, 366 patients (mean age 62.5 years) underwent uni- or bilateral nerve-sparing RRP at our institution. Indication for nerve-sparing procedure was based on the results of a multivariate classification and regression tree analysis (CART). For evaluation of post-operative patient-reported rates of sexual and erectile function non-validated and validated questionnaires (IIEF 5) were administered after a follow-up of 12 months. Data of five operation periods were analysed. RESULTS The unilateral procedure resulted in rates of 13-29% of erections sufficient for unassisted intercourse. Some degree of tumescence was reported by 37-73% of the remaining patients. Bilateral nerve-sparing procedures were almost exclusively performed in periods 3-5, only four patients of period 2 received the bilateral procedure. Here, rates of erections sufficient for intercourse were 25% (period 2), 61% (period 3), 50% (period 4), and 52% (period 5), respectively. Patients with grades 4 and 5 erections had IIEF scores of 19.2 and 20.2 and patients without rigidity or tumescence had scores of 5.7 and 7.0 after uni- and bilateral nerve-sparing procedure, respectively. Patients <60 years of age had better erections than those > or =60 (unilateral: 19% versus 13%, bilateral 45% versus 38%). CONCLUSION Compared to a unilateral nerve-sparing procedure, the bilateral nerve-sparing technique revealed much better results inasmuch as about 50% of the patients reported recovery of erections sufficient for sexual intercourse without use of sexual aids.

Critical assessment of preoperative urinary prostate cancer antigen 3 on the accuracy of prostate cancer staging.

BACKGROUND Knowledge about the staging significance of the prostate cancer antigen 3 (PCA3) score to better identify pathologic features after radical prostatectomy (RP) is limited and controversial. OBJECTIVE Our aim was to study the clinical staging significance of PCA3 to identify pathologic favorable and/or unfavorable features in the RP specimen. DESIGN, SETTING, AND PARTICIPANTS Complete retrospective clinical and pathologic data of consecutive men who had undergone RP from three tertiary referral centers including preoperative PCA3 scores (n=305) and computer-assisted planimetrically measured tumor volume data (n=160) were available. INTERVENTION All patients were treated with RP. MEASUREMENTS PCA3 scores were assessed using the PROGENSA assay (Gen-Probe, San Diego, CA, USA). Beyond standard risk factors (age, digital rectal examination, prostate-specific antigen, prostate volume, biopsy Gleason score, percentage of positive cores), five different PCA3 codings were used in logistic regression models to identify five distinct pathologic end points: (1) low-volume disease (<0.5 ml), (2) insignificant prostate cancer (PCa) according to the Epstein criteria, (3) extracapsular extension (ECE), (4) seminal vesicle invasion (SVI), and (5) aggressive disease defined as Gleason sum ≥7. Accuracy estimates of each end point were quantified using the area under the curve (AUC) of the receiver operator characteristic analysis in models with and without PCA3. RESULTS AND LIMITATIONS PCA3 scores were significantly lower in low-volume disease and insignificant PCa (p ≤ 0.001). AUC of multivariable low-volume disease (+2.4 to +5.5%) and insignificant PCa models (+3 to +3.9%) increased when PCA3 was added to standard clinical risk factors. In contradistinction, regardless of its coding, PCA3 scores were not significantly elevated in pathologically confirmed ECE (p=0.4) or SVI (p=0.5), respectively. Higher PCA3 scores were associated with aggressive disease (p<0.001). Importantly, the addition of PCA3 to multivariable intermediate- and high-grade models did not improve prediction. Despite reporting the largest pathologic PCA3 study, the main limitation resides in its small sample size. CONCLUSIONS PCA3 was confirmed as a valuable predictor of pathologically confirmed low-volume disease and insignificant PCa. Further exploration of its role as an additional marker to select patients for active surveillance may be warranted. In contradistinction, assessment of pathologically advanced or aggressive PCa is not improved using PCA3.

Downsides of Robot-assisted Laparoscopic Radical Prostatectomy: Limitations and Complications

CONTEXT Robot-assisted laparoscopic radical prostatectomy (RALP) using the da Vinci Surgical System (Intuitive Surgical, Sunnyvale, CA, USA) is now in widespread use for the management of localised prostate cancer (PCa). Many reports of the safety and efficacy of this procedure have been published. However, there are few specific reports of the limitations and complications of RALP. OBJECTIVE The primary purpose of this review is to ascertain the downsides of RALP by focusing on complications and limitations of this approach. EVIDENCE ACQUISITION A Medline search of the English-language literature was performed to identify all papers published since 2001 relating to RALP. Papers providing data on technical failures, complications, learning curve, or other downsides of RALP were considered. Of 412 papers identified, 68 were selected for review based on their relevance to the objective of this paper. EVIDENCE SYNTHESIS RALP has the following principal downsides: (1) device failure occurs in 0.2-0.4% of cases; (2) assessment of functional outcome is unsatisfactory because of nonstandardised assessment techniques; (3) overall complication rates of RALP are low, although higher rates are noted when complications are reported using a standardised system; (4) long-term oncologic data and data on high-risk PCa are limited; (5) a steep learning curve exists, and although acceptable operative times can be achieved in <20 cases, positive surgical margin (PSM) rates may require experience with >80 cases before a plateau is achieved; (6) robotic assistance does not reduce the difficulty associated with obese patients and those with large prostates, middle lobes, or previous surgery, in whom outcomes are less satisfactory than in patients without such factors; (7) economic barriers prevent uniform dissemination of robotic technology. CONCLUSIONS Many of the downsides of RALP identified in this paper can be addressed with longer-term data and more widespread adoption of standardised reporting measures. The significant learning curve should not be understated, and the expense of this technology continues to restrict access for many patients.