A 4Kscore Cut-off of 7.5% for Prostate Biopsy Decisions Provides High Sensitivity and Negative Predictive Value for Significant Prostate Cancer.

OBJECTIVE: To evaluate the 4Kscore test's low risk cut-off of 7.5% as the indication to proceed with a prostate biopsy by combining data from 2 independent prospective multicentre trials in the United States which have validated the 4Kscore test as a continuous score to predict clinically significant prostate cancer. MATERIALS AND METHODS: We analyzed the data from 2 prospective multicenter trials in the United states to determine the number of men who could safely avoid a prostate biopsy and the presence of clinically significant cancers detected, at a 4Kscore cut-off of 7.5%. We evaluated this in the entire cohort, and 3 subgroups of men aged 45-75 years with a total prostate specific antigen between 3.0 and 10.0 ng/mL, African American, and non-African American men. RESULTS: The analysis included 1378 patients. The combination analysis at a 7.5% threshold to decide upon a prostate biopsy, was associated with a 32% biopsy reduction. A total of 21 men (4.8%) with a low risk 4Kscore had International society of Urological Pathology, prostate cancer Grade group (GG) 2 or 3 cancer, leading to a sensitivity of 94% for detecting GG ≥2 cancer, and a negative predictive value of 95%. There were no GG ≥4 cancers with a low risk 4Kscore. Analyses in various subgroups afforded similar results. CONCLUSION: A 4Kscore test cut-off of 7.5% allowed a significant biopsy reduction, while maintaining high sensitivity and NPV for detecting and ruling out aggressive prostate cancer.

Clinical Proof-of-concept of a Novel Platform Utilizing Biopsy-derived Live Single Cells, Phenotypic Biomarkers, and Machine Learning Toward a Precision Risk Stratification Test for Prostate Cancer Grade Groups 1 and 2 (Gleason 3 + 3 and 3 + 4).

OBJECTIVE: To examine the ability of a novel live primary-cell phenotypic (LPCP) test to predict postsurgical adverse pathology (P-SAP) features and risk stratify patients based on SAP features in a blinded study utilizing radical prostatectomy (RP) surgical specimens. METHODS: Two hundred fifty-one men undergoing RP were enrolled in a prospective, multicenter (10), and proof-of-concept study in the United States. Fresh prostate samples were taken from known areas of cancer in the operating room immediately after RP. Samples were shipped and tested at a central laboratory. Utilizing the LPCP test, a suite of phenotypic biomarkers was analyzed and quantified using objective machine vision software. Biomarkers were objectively ranked via machine learning-derived statistical algorithms (MLDSA) to predict postsurgical adverse pathological features. Sensitivity and specificity were determined by comparing blinded predictions and unblinded RP surgical pathology reports, training MLDSAs on 70% of biopsy cells and testing MLDSAs on the remaining 30% of biopsy cells across the tested patient population. RESULTS: The LPCP test predicted adverse pathologies post-RP with area under the curve (AUC) via receiver operating characteristics analysis of greater than 0.80 and distinguished between Prostate Cancer Grade Groups 1, 2, and 3/Gleason Scores 3 + 3, 3 + 4, and 4 + 3. Further, LPCP derived-biomarker scores predicted Gleason pattern, stage, and adverse pathology with high precision-AUCs>0.80. CONCLUSION: Using MLDSA-derived phenotypic biomarker scores, the LPCP test successfully risk stratified Prostate Cancer Grade Groups 1, 2, and 3 (Gleason 3 + 3 and 7) into distinct subgroups predicted to have surgical adverse pathologies or not with high performance (>0.85 AUC).

The 4Kscore Predicts the Grade and Stage of Prostate Cancer in the Radical Prostatectomy Specimen: Results from a Multi-institutional Prospective Trial.

BACKGROUND: The 4Kscore accurately predicts aggressive prostate cancer (PCa) on prostate biopsy. OBJECTIVE: We assessed how well the 4Kscore predicts pathology at radical prostatectomy (RP). DESIGN, SETTING, AND PARTICIPANTS: Among 1312 men who prospectively underwent a 4Kscore and biopsy of the prostate at 26 sites throughout the United States from October 2013 to April 2014, we selected men who were diagnosed with cancer and underwent RP. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary outcome was the presence of high-grade PCa or extracapsular extension. We assessed the association between the 4Kscore and the grade and extent of PCa at RP using the Wilcoxon rank sum test. We used logistic regression to investigate the added value of the 4Kscore in predicting a high-grade or non-organ-confined tumor when added to available postbiopsy clinical predictive tools. RESULTS AND LIMITATIONS: A total of 144 men were diagnosed with PCa and underwent RP. Higher 4Kscores were associated with higher grade at RP. For men with Gleason scores ≥6, 7, and 8 cancers in the surgical specimen, the median 4Kscores were 7% (interquartile range [IQR]: 4-2), 25% (IQR: 12-38), and 47% (IQR: 24-66) (p<0.0001), respectively. The median 4Kscore among men with non-organ-confined cancer was significantly higher then men with organ-confined cancers (36% [IQR: 19-58] vs 19% [IQR: 9-35]; p=0.002). The 4Kscore did not significantly add to available clinical prediction tools for determining the likelihood of a high grade or non-organ-confined cancer; however, we were limited by a small sample size for this analysis. CONCLUSIONS: In a subset of men who underwent RP, the 4Kscore was significantly associated with pathologic grade and extracapsular extension in the surgical specimen, with higher scores associated with higher grade and more aggressive histology. The 4Kscore test may be helpful in selecting men who are likely to have adverse pathologic features at RP that may preclude them from being safely observed. PATIENT SUMMARY: Among men with prostate cancer who underwent removal of the prostate, the 4Kscore was associated with the final grade and extent of cancer.

The 4Kscore blood test accurately identifies men with aggressive prostate cancer prior to prostate biopsy with or without DRE information.

INTRODUCTION: The 4Kscore Test is a prebiopsy blood test that incorporates four prostate protein biomarkers along with patient clinical information to determine a man's risk for high-grade, aggressive (Gleason ≥7) prostate cancer. However, some men likely to benefit from the test may be seen in primary care settings where the digital rectal examination (DRE) information is not always obtained. In this study, we assessed the clinical validity of the 4Kscore Test when the DRE information was not included in the algorithm. METHODS: The Prospective 4Kscore Validation Study enrolled 1012 men scheduled for prostate biopsy across 26 urology practices in the United States. The 4Kscore was calculated for each patient with and without DRE information. The primary outcome was Gleason ≥7 prostate cancer on prostate biopsy. The contribution of DRE to the predictive accuracy of the test was evaluated by area under the receiver operating curve (AUC-ROC), risk calibration and clinical consequences. RESULTS: High-grade, aggressive prostate cancer was found in 231 (23%) of the 1012 patients. Both versions of the 4Kscore Test, with and without DRE, showed excellent discrimination (AUC=0.821 with DRE and AUC=0.818 without DRE input) and excellent calibration. No clinically significant difference was found between the two versions of the 4Kscore. CONCLUSIONS: The 4Kscore Test algorithm, whether DRE findings are available or not, performs well in predicting a man's risk of high-grade, aggressive prostate cancer. Patients who are suspected of having aggressive prostate cancer can safely have their risk better defined by 4Kscore even if a DRE has not been performed recently.

Rapid and Short-term Extracellular Matrix-mediated In Vitro Culturing of Tumor and Nontumor Human Primary Prostate Cells From Fresh Radical Prostatectomy Tissue.

OBJECTIVE: To culture prostate cells from fresh biopsy core samples from radical prostatectomy (RP) tissue. Further, given the genetic heterogeneity of prostate cells, the ability to culture single cells from primary prostate tissue may be of importance toward enabling single-cell characterization of primary prostate tissue via molecular and cellular phenotypic biomarkers. METHODS: A total of 260 consecutive tissue samples from RPs were collected between October 2014 and January 2016, transported at 4°C in serum-free media to an off-site central laboratory, dissociated, and cultured. A culture protocol, including a proprietary extracellular matrix formulation (ECMf), was developed that supports rapid and short-term single-cell culture of primary human prostate cells derived from fresh RP samples. RESULTS: A total of 251 samples, derived from RP samples, yielded primary human tumor and nontumor prostate cells. Cultured cells on ECMf exhibit (1) survival after transport from the operating room to the off-site centralized laboratory, (2) robust (>80%) adhesion and survival, and (3) expression of different cell-type-specific markers. Cells derived from samples of increasing Gleason score exhibited a greater number of focal adhesions and more focal adhesion activation as measured by phospho-focal adhesion kinase (Y397) immunofluorescence when patient-derived cells were cultured on ECMf. Increased Ki67 immunofluorescence levels were observed in cells derived from cancerous RP tissue when compared to noncancerous RP tissue. CONCLUSION: By utilizing a unique and defined extracellular matrix protein formulation, tumor and nontumor cells derived from primary human prostate tissue can be rapidly cultured and analyzed within 72 hours after harvesting from RP tissue.

Clinical performance of the 4Kscore Test to predict high-grade prostate cancer at biopsy: A meta-analysis of us and European clinical validation study results.

The 4Kscore® Test (OPKO Diagnostics, Woburn, MA) is a blood test utilized prior to a prostate biopsy to determine a patient's risk of high-grade prostate cancer (PCa) should the biopsy be performed, thus providing critical information in the clinical management of men with a suspicious prostate-specific antigen value or digital rectal examination result. Multiple US and European clinical studies confirmed that a prebiopsy 4Kscore Test has a high degree of discrimination for a subsequent discovery of high-grade (Gleason score ≥7) PCa. The aim of this study was to evaluate the predictive accuracy of the 4Kscore Test to discriminate between patients with and without high-grade PCa based on published clinical validation studies. A systematic review and meta-analysis of the eligible 4Kscore Test clinical validation studies was conducted. The pooled area under the curve (AUC) of the 4Kscore Test as reported from all the studies, and the heterogeneity among these studies were analyzed and repeated for subgroups of the studies. Twelve clinical validation studies were included in the meta-analysis, comprising a total of 11,134 patients. The pooled AUC to discriminate for high-grade PCa for all 12 studies was 0.81 (fixed effects 95% CI, 0.80-0.83). Restricting the analysis to the six publications that used the contemporary 4Kscore Test algorithm led to very similar results (AUC 0.81; 95% CI, 0.79-0.83). Heterogeneity was high among all of the 12 studies, as well as among the six publications that used the contemporary 4Kscore Test (Cochrane's Q test, p = 0.001 for both); however, in both cases, after exclusion of a single outlying study with a much lower AUC, heterogeneity was no longer significant (p = 0.08 and p = 0.21). The pooled estimate of 4Kscore Test discrimination (AUC) for high-grade PCa is >0.80, and is consistent across multiple US and European clinical validation studies.

The 4Kscore® Test Reduces Prostate Biopsy Rates in Community and Academic Urology Practices.

There is significant concern regarding prostate cancer screening because of the potential for overdiagnosis and overtreatment of men who are discovered to have abnormal prostate specific antigen (PSA) levels and/or digital rectal examination (DRE) results. The 4Kscore® Test (OPKO Diagnostics, LLC) is a blood test that utilizes four kallikrein levels plus clinical information in an algorithm to calculate an individual's percentage risk (< 1% to > 95%) for aggressive prostate cancer (Gleason score ≥ 7) on prostate biopsy. The 4Kscore Test, as a follow-up test after abnormal PSA and/or DRE test results, has been shown to improve the specificity for predicting the risk of aggressive prostate cancer and reduce unnecessary prostate biopsies. A clinical utility study was conducted to assess the influence of the 4Kscore Test on the decision to perform prostate biopsies in men referred to urologists for abnormal PSA and/or DRE results. The study population included 611 patients seen by 35 academic and community urologists in the United States. Urologists ordered the 4Kscore Test as part of their assessment of men referred for abnormal PSA and/or DRE test results. Results for the patients were stratified into low risk (< 7.5%), intermediate risk (7.5%-19.9%), and high risk (≥ 20%) for aggressive prostate cancer. The 4Kscore Test results influenced biopsy decisions in 88.7% of the men. Performing the 4Kscore Test resulted in a 64.6% reduction in prostate biopsies in patients; the actual percentage of cases not proceeding to biopsy were 94.0%, 52.9%, and 19.0% for men who had low-, intermediate-, and high-risk 4Kscore Test results, respectively. A higher 4Kscore Test was associated with greater likelihood of having a prostate biopsy (P < 0.001). Among the 171 patients who had a biopsy, the 4Kscore risk category is strongly associated with biopsy pathology. The 4Kscore Test, as a follow-up test for an abnormal PSA and/or DRE results, significantly influenced the physician and patient shared decision in clinical practice, which led to a reduction in prostate biopsies while increasing the probability of detecting aggressive cancer.

A multi-institutional prospective trial in the USA confirms that the 4Kscore accurately identifies men with high-grade prostate cancer.

BACKGROUND: The 4Kscore combines measurement of four kallikreins in blood with clinical information as a measure of the probability of significant (Gleason ≥7) prostate cancer (PCa) before prostate biopsy. OBJECTIVE: To perform the first prospective evaluation of the 4Kscore in predicting Gleason ≥7 PCa in the USA. DESIGN, SETTING, AND PARTICIPANTS: Prospective enrollment of 1012 men scheduled for prostate biopsy, regardless of prostate-specific antigen level or clinical findings, was conducted at 26 US urology centers between October 2013 and April 2014. INTERVENTION: The 4Kscore. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary outcome was Gleason ≥7 PCa on prostate biopsy. The area under the receiver operating characteristic curve, risk calibration, and decision curve analysis (DCA) were determined, along with comparisons of probability cutoffs for reducing the number of biopsies and their impact on delaying diagnosis. RESULTS AND LIMITATIONS: Gleason ≥7 PCa was found in 231 (23%) of the 1012 patients. The 4Kscore showed excellent calibration and demonstrated higher discrimination (AUC 0.82) and net benefit compared to a modified Prostate Cancer Prevention Trial Risk Calculator 2.0 model and standard of care (biopsy for all men) according to DCA. A possible reduction of 30-58% in the number biopsies was identified with delayed diagnosis in only 1.3-4.7% of Gleason ≥7 PCa cases, depending on the threshold used for biopsy. Pathological assessment was performed according to the standard of care at each site without centralized review. CONCLUSION: The 4Kscore showed excellent diagnostic performance in detecting significant PCa. It is a useful tool in selecting men who have significant disease and are most likely to benefit from a prostate biopsy from men with no cancer or indolent cancer. PATIENT SUMMARY: The 4Kscore provides each patient with an accurate and personalized measure of the risk of Gleason ≥7 cancer to aid in decision-making regarding the need for prostate biopsy.

The Kallikrein Panel for prostate cancer screening: its economic impact.

BACKGROUND: Current diagnostic testing for prostate cancer results in numerous unnecessary biopsy procedures and creates a substantial financial burden. A statistical prediction model for prostate cancer has been developed, based on four Kallikrein markers in blood. This systematic review and meta-analysis examines the aggregated results from published studies of the Kallikrein Panel. METHODS: Literature searches to identify relevant studies were conducted. A meta-analysis of the results was performed using inverse variance, mean difference with corresponding 95% confidence intervals (CI). The results of the meta-analysis were used to assess the Kallikrein Panel's effect on healthcare costs. RESULTS: The Kallikrein Panel has been evaluated in more than 8,500 patients (2,780 with prostate cancer and 598 with high grade prostate cancer). Meta-analysis demonstrates a statistically significant improvement of 8-10% in predictive accuracy. In addition, 48% to 56% of current prostate biopsies could be avoided. Use of the Kallikrein Panel could result in annual US savings approaching $1 billion. CONCLUSIONS: The Kallikrein Panel has the potential to improve patient outcomes and reduce costs. The panel provides significantly improved specificity. Because the Kallikrein Panel has been studied in a range of clinical settings, it is a test that could be readily and widely used in practice.