From prostate specific antigen to genomic signatures: Advances in biomarkers for prostate cancer diagnosis and prognosis.

A recent surge in biomarkers to aid management of men with prostate cancer has occurred. Their applications are varied and not all tests are applicable to the active surveillance setting. To review primary evidence on genetic and immunohistochemical biomarkers, and their role on patient selection and risk stratification for men on active surveillance for prostate cancer. A PubMed electronic search using the terms (biomarker or genetic or histopathological) AND ("prostate cancer" AND "active surveillance") was performed from inception to April 2015. Of the biomarkers reviewed, Prostate Health Index (PHI) and Oncotype DX Genomic Prostate Score (GPS), were identified to currently hold greatest potential benefit to aid risk stratification of men for AS. Higher PHI, at baseline and during follow-up, was shown to predict pathological upgrading at rebiopsy at two single institutions, but with small cohorts (n<200). The Oncotype DX GPS test has been validated on men suitable for AS but having upfront radical prostatectomy. Increase in GPS was shown to predict upgrading and upstaging at radical prostatectomy and biochemical recurrence post radical prostatectomy. Prospective validation in AS cohorts is yet to be performed. PHI and Oncotype DX GPS show promise in aiding risk stratification for men on AS. However, larger prospective studies in AS cohorts are needed. Integration of biomarkers with existing clinical and imaging models remains a challenge.

Utility of the Oncotype DX® Prostate Cancer Assay in Clinical Practice for Treatment Selection in Men Newly Diagnosed with Prostate Cancer: A Retrospective Chart Review Analysis

Introduction: The low specificity of PSA in prostate cancer (PCa) screening has caused excessive biopsies and PCa over-detection. PHI is more specific for clinically significant (cs) PCa (i.e. Gleason &amp;gt;6 PCa) and includes serum PSA, [-2]proPSA, and free PSA in its formula. Validation studies in diverse populations have suggested that PHI should be used as a reflex test and the optimal cutoffs for PHI vary across ethnic groups, but have not been determined in Black men. We sought to 1) assess the distributions of PHI and PSA in healthy controls and men with high-grade PCa and 2) assess the accuracy of PHI vs. PSA for detection of csPCa in Black men with elevated PSA. Methods: The present study population consists of two biopsy-naïve cohorts. The first cohort serves as healthy controls and includes Black men with PHI and PSA drawn at community screening events through the social networks of eight lay Black male Citizen Scientists. The second PHI Biopsy Study cohort consists of Black men referred with elevated PSA and/or abnormal digital rectal exam (DRE) who had PHI drawn immediately before prostate biopsy. We excluded men with prior biopsies or known PCa. Distributions of PHI and PSA were compared across controls and men with negative biopsies, Gleason 6 PCa and csPCa. Among men with biopsy, we compared the area under the receiver operating characteristics curves (AUC) for PSA and PHI for detecting csPCa and assessed specificity at selected sensitivities as a proxy of avoided biopsies. We descriptively assessed theoretically avoided biopsies and missed csPCa at previously established PHI cut points [27.0, 28.6, 29.9, and 35.0]. Results: For the first objective, 139 men (42.5%) were included as controls from the Citizens Scientist Study and 188 (57.5%) were from the PHI Biopsy Study cohort, out of which 82 (43.6%) had a negative biopsy for PCa, 40 (21.1%) had low-grade PCa, and 66 (35.1%) had a Gleason &amp;gt;6 PCa. Compared to the healthy control group, the PHI Biopsy Study cohort was older (median age 61 vs. 55 years), with higher PSA levels (7.1ng/mL vs. 0.9ng/mL) and PHI scores (61.1 vs. 20.1), and more commonly had a family history of PCa (19.4% vs. 5.0%) and benign prostatic hyperplasia diagnosis (21.3% vs. 2.2%) (all p&amp;lt;0.001). Relative to PSA, PHI has a higher degree of overlap in the distribution between controls and csPCas (p &amp;lt;0.05), suggesting PHI would not perform well as a primary screening test in Blacks. In men with PSA between 4-10, PHI outperformed PSA in the detection of HGPCa with an AUC of 0.70 (95% CI: 0.59-0.81) compared to 0.57 (95% CI: 0.46-0.69). As a reflex test in men with PSA of 4-10ng/mL and normal DRE, a PHI cutoff of 35.0 would spare 20 (27.8%) low-risk men a biopsy while missing 2 (7.4%) csPCas. Conclusion: PHI should not be used for primary screening but has higher accuracy and specificity than PSA in Black men with PSA levels of 4-10ng/mL as a reflex test. At a cutoff of 35.0, 28% of low-risk men avoid biopsy while missing 7% of csPCas. Citation Format: Samuel Carbunaru, Oluwarotimi Nettey, Edward M Schaeffer, Peter H Gann, Michael Abern, Courtney M.P Hollowell, Karriem Watson, Tiffany McDowell, Rick A Kittles, Adam B Murphy. Performance of the prostate health index (PHI) assay in black men [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr A066.

122 Background: With evidence showing over treatment, more patients are choosing active surveillance (AS) for intermediate or lower risk prostate cancer (CaP). Genomic profiling is offered to risk stratify patients to aid in management decision−making. This study reports risk discrepancies between National Comprehensive Cancer Network (NCCN) criteria and OncotypeDx Genomic Prostate Score (GPS) and how this influences decision−making in our CaP population. Methods: An inception cohort study was carried out on 56 patients with NCCN very low to intermediate risk CaP who were candidates for AS and underwent GPS testing on prostate biopsy specimens performed within 6mo of entry. GPS provided a score corresponding to a GPS-based risk stratification. Study endpoints: 1) distribution of GPS risk groups within each NCCN risk category; 2) frequency of change to lower or higher risk based on GPS; 3) effect of GPS on physician recommendations and patient choice on disease management. Results: 52/56 patients had sufficient carcinoma on biopsy for a GPS analysis. GPS reassigned risk in 23% (12/52) of patients, with 10 going from NCCN low risk to GPS very low risk and 2 assigned to a higher GPS risk profile (Table). AS was recommended in 19 patients with GPS very low risk group and 8 patients in the GPS-defined low risk group. Physicians recommended treatment to 7 patients with GPS intermediate risk. Patient choice was congruent with physician recommendation in all cases. No patients chose AS when assigned to a higher risk category. All 10 patients reassigned to a lower risk category chose AS. Conclusions: In this CaP cohort, assessment by GPS changed risk stratification in 23% of patients. Moving to a different risk category changed physician recommendation and patient choice in the corresponding direction (to surveillance or therapy) in all cases. More study and larger sample size are needed to fully assess the effect of GPS on clinical decision making. [Table: see text]

The diagnosis of prostate cancer (PCa) is currently based on serum PSA testing and/or abnormal digital rectal examination and histopathologic evaluation of prostate biopsies. The main drawback of PSA testing is the lack of specificity for PCa. To improve early detection of PCa more specific biomarkers are needed. In the past few years, many new promising biomarkers have been identified; however, to date, only a few have reached clinical practice. In this review, we discuss new blood-based and urinary biomarker models that are promising for usage in PCa detection, follow-up and treatment decision-making. These include Prostate Health Index (PHI), prostate cancer antigen 3 (PCA3), four-kallikrein panel (4K), transmembrane protease serine 2-ERG (TMPRSS2-ERG), ExoDx Prostate Intelliscore, SelectMDx and the Mi-Prostate score. Only few head-to-head studies are available for these new fluid-based biomarkers and/or models. The blood-based PHI and urinary PCA3 are two US Food and Drug Administration-approved biomarkers for diagnosis of PCa. In the second part of this review, we give an overview of published studies comparing these two available biomarkers for prediction of (1) PCa upon prostate biopsy, (2) pathological features in radical prostatectomy specimen and (3) significant PCa in patients eligible for active surveillance. Studies show opposing results in comparison of PHI with PCA3 for prediction of PCa upon initial and repeat prostate biopsy. PHI and PCA3 are able to predict pathological findings on radical prostatectomy specimen, such as tumor volume and Gleason score. Only PHI could predict seminal vesicle invasion and only PCA3 could predict multifocality. There is some evidence that PHI outperforms PCA3 in predicting significant PCa in an active surveillance population. Future research should focus on independent validation of promising fluid-based biomarkers/models, and prospective comparison of biomarkers with each other.

Critical Appraisal of Prostate-specific Antigen in Prostate Cancer Screening: 20 Years Later

97 Background: The OncotypeDX Genomic Prostate Score (GPS) test is a RNA expression assay that can be performed on needle-core biopsies from men with prostate cancer (PCa). GPS has previously been validated as a predictor of adverse pathology in men with low-risk prostate cancer who undergo primary radical prostatectomy (RP). We sought to determine whether GPS was associated with increased risk of adverse pathology for men enrolled on active surveillance (AS) who undergo delayed RP. Methods: Of 1,662 men enrolled on AS at the University of California San Francisco (UCSF) who consented for prospective data collection, we evaluated 215 men on AS with Gleason score (GS) 3+3 and GS 3+4 PCa who underwent GPS testing at diagnostic or confirmatory biopsy (ie. within 1 year). Patients had at least 6 biopsy cores sampled and ≤ 33% positive cores, stage T1 or T2 disease, PSA &lt; 20, and clinical Cancer of the Prostate Risk Assessment (CAPRA) score &lt; 6. The primary outcome was adverse pathology at delayed RP, defined as GS ≥ 4+3, stage ≥ pT3a or pN1. We performed Cox proportional hazards regression, and inverse probability censored weights (IPCW) models to evaluate association between GPS and adverse pathology, adjusting for CAPRA score. Results: 72 percent (N=154) of the cohort had GS 3+3, and 28 percent (N=61) had GS 3+4. 83 percent of men (N=179) were low risk, and 17 percent of men (N=36) were intermediate risk by CAPRA scoring. Median GPS was 26.4 (interquartile range [IQR]: 18.8, 34.6). Median time from diagnosis to RP was 23 months (IQR: 15, 40). 121 men had adverse pathology on delayed RP at a median time of 27 months (IQR 16, 43) to prostatectomy. In a Cox-proportional hazards regression adjusted for CAPRA, GPS was associated with increased risk of adverse pathology at delayed RP (Hazard Ratio [HR] per 5 units: 1.12, 95 Confidence Interval [CI]: 1.05, 1.20, p &lt; 0.01). CAPRA score was not associated with adverse pathology (p=0.09). IPCW model findings were very similar to Cox results. Conclusions: In patients who undergo RP after a relatively short period of AS, a higher GPS is associated with increased risk for adverse pathology on delayed RP.

Objective: To validate the 17-gene Oncotype DX Genomic Prostate Score (GPS) biopsy-based gene expression assay as a predictor of adverse pathology (AP: Pathologic Gleason score ≥4+3, presence of any Gleason 5, and/or ≥pT3) in African American (AA) men. Methods: Between February 2009 and September 2014, AA and European American (EA) men with very low, low, and intermediate risk prostate cancer (PCa) enrolled in a multi-institutional prospective study of vitamin D impacts of biopsy outcomes. The subset who proceeded to immediate radical prostatectomy (RP) after biopsy with available biopsy tumor blocks was included in a comparative effectiveness analysis of GPS on biopsy and its association with surgical AP on RP using logistic regression and receiver operating characteristic curves. Multiplicative interactions tested for differential prediction of GPS accuracy by race (AA vs. EA). Results: Overall, 102 AA and 76 EA men elected RP, out of which 51 (47.2%) had AP. GPS result was a significant predictor of AP (odds ratio per 20 GPS units [OR/20 units] in AA: 4.78; 95% CI 1.8-12.5, P =0.001; and EA: 4.41; 95% CI 1.6-11.9, P =0.003) in univariable analysis. On multivariate analysis, there was a significant interaction between GPS and race (P=0.01). On race stratified binary logistic regression, AP remained significant after adjustment for NCCN risk group in both AA and EA men (OR/20 units in AA: 3.29; 95% CI 1.2-9.1, P =0.02; and EA: 4.24; 95% CI 1.4-12.6, P =0.01). Area under the curves for AP using GPS/20 units was 0.719 for AAs vs. 0.745 for EAs (P=0.39). Conclusion: In this AA validation study, the Oncotype Dx PCa assay was confirmed as an independent predictor of AP at prostatectomy in AA and EA men with similar predictive accuracy, though there was evidence of effect modification by race. Citation Format: Samuel Carbunaru, Virgilia Marcias, Peter Gann, Roohollah Sharifi, Ximing Yang, Michael Dixon, Chase Gorbein, Borko Jovanovic, Andre Kajdacsy-Balla, Adam B. Murphy. Oncotype DX assay has similar predictive accuracy for adverse pathology at radical prostatectomy in African American and European American men [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr A067.

-2]Proenzyme Prostate Specific Antigen is More Accurate Than Total and Free Prostate Specific Antigen in Differentiating Prostate Cancer From Benign Disease in a Prospective Prostate Cancer Screening Study

Correlation of a Commercial Genomic Risk Classifier with Histological Patterns in Prostate Cancer

A Multicenter Study of [-2]Pro-Prostate Specific Antigen Combined With Prostate Specific Antigen and Free Prostate Specific Antigen for Prostate Cancer Detection in the 2.0 to 10.0 ng/ml Prostate Specific Antigen Range

A 17-gene Panel for Prediction of Adverse Prostate Cancer Pathologic Features: Prospective Clinical Validation and Utility

Although prostate-specific antigen-based prostate cancer screening had a positive impact in reducing prostate cancer mortality, it also led to overdiagnosis, overtreatment and a significant number of unnecessary biopsies. In the post-prostate-specific antigen era, new biomarkers have emerged that can complement the information given by prostate-specific antigen, towards a better cancer diagnostic specificity, and also allowing a better estimate of the aggressiveness of the disease and its clinical outcome. That means those markers have the potential to assist the clinician in the decision-making processes, such as whether or not to perform a biopsy, and to make the best treatment choice among the new therapeutic options available, including active surveillance in lower risk disease. In this article, we will review several of those more recent diagnostic markers (4Kscore®, [-2]proPSA and Prostate Health Index, SelectMDx®, ConfirmMDx®, Progensa® Prostate Cancer Antigen 3, Mi-Prostate Score, ExoDx™ Prostate Test, the Stockholm3 test and ERSPC risk calculators) and prognostic markers (OncotypeDX® Genomic Prostate Score, Prolaris®, Decipher® and ProMark®). We will also address some new liquid biopsy approaches - circulating tumour cells and cell-free DNA - with a potential role in metastatic castration-resistant prostate cancer and will briefly give some future perspectives, mostly outlooking epigenetic markers.

Prostate cancer (PCa) is the second most common cancer in men worldwide. A large proportion of PCa are latent, never destined to progress or affect the patients’ life. It is of utmost importance to identify which PCa are destined to progress and which would benefit from an early radical treatment. Prostate-specific antigen (PSA) remains the most used test to detect PCa. Its limited specificity and an elevated rate of overdiagnosis are the main problems associated with PSA testing. New PCa biomarkers have been proposed to improve the accuracy of PSA in the management of early PCa. Commercially available biomarkers such as PCA3 score, Prostate Health Index (PHI), and the four-kallikrein panel are used with the purpose of reducing the number of unnecessary biopsies and providing information related to the aggressiveness of the tumor. The relationship with PCa aggressiveness seems to be confirmed by PHI and the four-kallikrein panel, but not by the PCA3 score. In this review, we also summarize new promising biomarkers, such as PSA glycoforms, TMPRSS2:ERG fusion gene, microRNAs, circulating tumor cells, androgen receptor variants, and PTEN gene. All these emerging biomarkers could change the management of early PCa, offering more accurate results than PSA. Nonetheless, large prospective studies comparing these new biomarkers among them are required to know their real value in PCa detection and prognosis.

The Oncotype Dx Genomic Prostate Score (GPS) is a 17-gene relative expression assay that predicts adverse pathology at prostatectomy. We conducted a novel randomized controlled trial to assess the impact of GPS on urologist's treatment preference for favorable risk prostate cancer (PCa): active surveillance versus active treatment (i.e., prostatectomy/radiation). This is a secondary endpoint from the ENACT trial which recruited from three Chicago hospitals from 2016 to 2019. Ten urologists along with men with very low to favorable-intermediate risk PCa were included in the study. Participants were randomly assigned to standardized counseling with or without GPS assay. The main outcome was urologists' preference for active treatment at Visit 2 by study arm (GPS versus Control). Multivariable best-fit binary logistic regressions were constructed to identify factors independently associated with urologists' treatment preference. Two hundred men (70% Black) were randomly assigned to either the Control (96) or GPS arm (104). At Visit 2, urologists' preference for prostatectomy/radiation almost doubled in the GPS arm to 29.3% (29) compared to 14.1% (13) in the Control arm (p = 0.01). Randomization to the GPS arm, intermediate NCCN risk level, and lower patient health literacy were predictors for urologists' preference for active treatment. Limitations included sample size and number of urologists. In this study, we found that GPS testing reduced urologists' likelihood to prefer active surveillance. These findings demonstrate how obtaining prognostic biomarkers that predict negative outcomes before treatment decision-making might influence urologists' preference for recommending aggressive therapy in men eligible for active surveillance.