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

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 < 20, and clinical Cancer of the Prostate Risk Assessment (CAPRA) score < 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 < 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.

A 17-Gene Panel Genomic Prostate Score Has Similar Predictive Accuracy for Adverse Pathology at Radical Prostatectomy in African American and European American Men

100 Background: We validated a biopsy-based assay as a predictor of PCa aggressiveness in two independent patient cohorts. Using GPS with NCCN risk group, the test provides an estimate of likelihood of favorable pathology (LFP) in low-intermediate risk PCa based on data from the first validation study. The second study re-confirmed the association between GPS and LFP. We combined information from both studies to provide more precise estimates of LFP, and examined predictive models using GPS with other clinical risk tools. Methods: Patient-specific MA provides precision-weighted predictions for individual patients using data from multiple studies (Crager and Tang, J. Appl. Stat. 2014). MA was performed on the two validation studies (732 patients total) using GPS (scale 0-100) with CAPRA score, NCCN risk group, or AUA/EAU risk group as predictors of LFP (Gleason score 3+3 or 3+4, organ-confined disease). Decision curves were calculated using the MA risk estimates. Results: MA provided more precise estimates of LFP with narrower confidence intervals (CIs) than either study alone (median width 24% narrower than the smaller of the two individual study CIs). GPS added significant predictive value for LFP to each of the 3 clinical classifiers. A model utilizing GPS and CAPRA provided the most risk discrimination. In decision-curve analysis, greater net benefit was shown when combining GPS with each clinical classifier compared with the clinical classifier alone. Over a wide range of threshold probabilities, incorporation of GPS would be expected to lead to fewer treatments of patients with favorable pathology without increasing the number of patients with adverse pathology left untreated. The proportion of men with MA-estimated LFP > 80% was 31% with GPS and CAPRA, and 23% with GPS and NCCN risk group; 11% were identified with LFP > 80% using NCCN risk group alone. Conclusions: Patient-specific MA of two independent studies provided more precise risk estimates reflecting the complete body of evidence. GPS adds predictive value to three clinical risk tools. The MA-estimated LFP identified more patients with an LFP > 80% than identified by clinical classifiers alone.

e16607 Background: The 17-gene Oncotype Dx Genomic Prostate Score® (GPS™) assay has been validated as a predictor of aggressive prostate cancer (PCa) in men treated with radical prostatectomy (RP) for clinically low and intermediate risk PCa. This study examined the performance of the GPS assay as a predictor of adverse pathology (AP) and biochemical recurrence (BCR)-free survival (BRFS), after adjusting for the presence of major comorbidities commonly seen in older men. Methods: Additional analyses were performed using data from a prior clinical validation study of the GPS assay. GPS values (scaled 0-100), determined from diagnostic biopsy tissue, were categorized into 3 levels: lowest quartile (Q1), middle quartiles (combined Q2-Q3) versus the highest quartile (Q4). Major comorbidities included heart disease, stroke, COPD, and other cancers. The associations between GPS result and the presence of ≥1 major comorbidity and outcomes were examined. AP was defined as high-grade (Gleason Score ≥ 4+3) and/or pT3 tumor. BCR was defined as 2 successive PSA levels > 0.2 ng/mL. Logistic regression analysis was used to examine AP; Cox proportional hazards analysis was used to model BRFS. Results: Among 389 eligible men, median age at diagnosis and follow-up time was 62 and 5.6 years, respectively. The prevalence of ≥1 major comorbidity differed significantly across GPS category, rising from 10.2% to 19.7% to 25.5% for GPS Quartiles 1, 2-3, and 4, respectively (p = 0.0024). However, presence of ≥1 major comorbidity was not a significant predictor of AP or BCR in multivariable models with GPS, age, race, and NCCN risk stratum. Men whose GPS result was in the highest quartile had 4-fold higher odds of AP (OR: 4.1; 95% CI = 2.1-7.99, p < 0.0001) at RP and a 3.5 times higher risk of BCR (HR = 3.49; 95% CI = 1.59-7.64, p = 0.002) compared to men in the lowest GPS quartile (Table 1). Conclusions: A high GPS result remains the strongest predictor of BCR and AP in this cohort of low and intermediate risk PCa men, after adjusting for the presence of major comorbidities. Further work will explore the relationships between specific comorbidities and metabolic syndrome, with GPS testing and PCa outcomes.

A Prospectively-Designed Study to Determine the Association of a 17-Gene Genomic Prostate Score with Recurrence Following Surgery for Localised Prostate Cancer (Pca)

A 17-Gene Genomic Prostate Score as a Predictor of Adverse Pathology in Men on Active Surveillance.

124 Background: A biopsy-based RT-PCR assay (Oncotype DX Prostate Assay) providing a Genomic Prostate Score (GPS) as a measure of tumor aggressiveness has been validated as a predictor of adverse pathologic and oncologic outcomes. We sought to evaluate the change in GPS results among men with favorable-risk prostate cancer (PCa) managed with active surveillance (AS). Methods: We identified men with low and intermediate-clinical risk PCa managed with AS at our institution receiving a minimum of two GPS tests on serial prostate biopsy. GPS ranges from 0 (least) to 100 (most aggressive disease). We described the change in assay results and clinical risk designation over time and reported the subsequent clinical outcome (definitive treatment versus continued AS). For men receiving treatment with radical prostatectomy (RP) the occurrence of adverse pathological findings was defined by the presence of high grade (Gleason pattern ≥ 4+3) or non-organ confined disease ( ≥ pT3a). Results: 31 men were identified who underwent serial GPS testing at a median of 12 months. The median change in GPS was an increase of 1 point (IQR -7, 13). Fourteen (45%) patients experienced an increase in NCCN risk classification, including 3 from very-low to intermediate and 11 from low to intermediate risk. Following serial GPS testing 7 patients (23%) underwent radical prostatectomy. Among surgically treated patients, 3 had adverse pathology due to pT3a disease and the mean change in GPS prior to treatment was an increase of 13 points (IQR -7, 18); all of whom were intermediate clinical risk at the time of surgery. This study was limited by the small sample size and the uncontrolled decision to pursue definitive therapy. Conclusions: Serial change in a tissue based gene expression assay on serial biopsy during AS was non-static. Magnitude of GPS change may identify men at risk for adverse pathological findings, although larger series are required to validate such an endpoint during AS.

A Biopsy-based 17-gene Genomic Prostate Score Predicts Recurrence After Radical Prostatectomy and Adverse Surgical Pathology in a Racially Diverse Population of Men with Clinically Low- and Intermediate-risk Prostate Cancer

262 Background: The 17-gene Genomic Prostate Score (GPS) test (scale 0-100) predicts adverse surgical pathology (AP) and recurrence in newly diagnosed low- and intermediate-risk PCa. Studies of the predictive value of the GPS test in men initially managed with AS are limited. Methods: Diagnostic biopsy tissue was obtained from 634 men enrolled at 8 sites in PASS. Time to AP (Gleason Grade Group (GG) ≥3, ≥pT3a, or N1) in men who underwent radical prostatectomy (RP) was the primary endpoint. All diagnostic biopsies and RP specimens were centrally reviewed. Multivariate regression models for interval censored data were used to evaluate the association between time to AP and GPS. Inverse probability of censoring weighting was applied to adjust for informative censoring. Association between GPS and time to Gleason score upgrade on surveillance biopsy was also evaluated using a Cox Proportional Hazards model. Results: GPS results were obtained for 432 men (median follow-up 4.6 [IQR: 2.9-6.2] years); 374 and 58 with GG 1 or 2 cancer, respectively; median PSA density (PSAD) was 0.11 [IQR: 0.08-0.15]; 101 men underwent RP with central pathology after a median of 2.1 [IQR: 1.3-4.3] years surveillance, and 52 (52%) men undergoing RP had AP. 167 men upgraded at a subsequent biopsy. No clinico-pathologic covariates were significantly associated with AP other than PSAD. GPS was significantly associated with time to AP (hazards ratio [HR]/20 GPS units: 1.96 [95% CI = 1.17-4.28]; p = 0.030), when adjusted for diagnostic GG, or for dichotomous PSAD ( < vs ≥ 0.15; HR: 1.83, 95% CI = 1.04-3.62; p = 0.046). GPS was not significantly associated with AP (HR: 1.61, 95% CI = 0.87-2.98; p = 0.12) when adjusted for continuous PSAD. No association, either univariable or multivariable, was observed between GPS and subsequent biopsy upgrade. Conclusions: In a cohort of men on AS, GPS was associated with time to AP when adjusted for diagnostic GG or dichotomous PSAD. GPS was not associated with surveillance biopsy GG upgrading or AP at surgery after adjustment for continuous PSAD, although a trend was seen for AP, suggesting an association may be seen in a larger study.

The 17-gene Oncotype DX Genomic Prostate Score (GPS) test predicts adverse pathology (AP) in patients with low-risk prostate cancer treated with immediate surgery. We evaluated the GPS test as a predictor of outcomes in a multicenter active surveillance cohort. Diagnostic biopsy tissue was obtained from men enrolled at 8 sites in the Canary Prostate Active Surveillance Study. The primary endpoint was AP (Gleason Grade Group [GG] ≥ 3, ≥ pT3a) in men who underwent radical prostatectomy (RP) after initial surveillance. Multivariable regression models for interval-censored data were used to evaluate the association between AP and GPS. Inverse probability of censoring weighting was applied to adjust for informative censoring. Predictiveness curves were used to evaluate how models stratified risk of AP. Association between GPS and time to upgrade on surveillance biopsy was evaluated using Cox proportional hazards models. GPS results were obtained for 432 men (median follow-up, 4.6 years); 101 underwent RP after a median 2.1 years of surveillance, and 52 had AP. A total of 167 men (39%) upgraded at a subsequent biopsy. GPS was significantly associated with AP when adjusted for diagnostic GG (hazards ratio [HR]/5 GPS units, 1.18; 95% CI, 1.04 to 1.44; P = .030), but not when also adjusted for prostate-specific antigen density (PSAD; HR, 1.85; 95% CI, 0.99 to 4.19; P = .066). Models containing PSAD and GG, or PSAD, GG, and GPS may stratify risk better than a model with GPS and GG. No association was observed between GPS and subsequent biopsy upgrade (P = .48). In our study, the independent association of GPS with AP after initial active surveillance was not statistically significant, and there was no association with upgrading in surveillance biopsy. Adding GPS to a model containing PSAD and diagnostic GG did not significantly improve stratification of risk for AP over the clinical variables alone.

104 Background: The biopsy-based GPS (scale 0-100) is validated as an independent predictor of adverse pathology in men with low- and intermediate-risk PCa. We wished to examine the association of GPS with BCR and CR in higher-risk disease. Methods: We performed exploratory analyses of data from a prior development study of radical prostatectomies from 441 men with AUA low-, intermediate- and high-risk disease, using a cohort sampling design (Klein et al. Eur Urol 2015). Multivariable Cox proportional hazards models were employed with the cohort sampling weights. Since these data were used in the selection of genes and coefficients for GPS, hazard ratios (HR) and other estimates based on GPS were corrected for regression to the mean (RM), and Storey’s method was applied to hypothesis tests for GPS to control the false discovery rate (FDR). Results: All estimates are RM-corrected. Broad, overlapping ranges of GPS values were observed across all AUA risk groups. GPS was strongly associated with BCR (HR 1.64 for 20 GPS units, p<0.001, FDR q-value < 0.1%) and CR (HR 2.79 for 20 GPS units, p < 0.001; FDR q-value < 0.1%), after adjusting for AUA risk group. Intermediate-risk patients with GPS > 40, who represented 41% of all intermediate-risk patients, had estimated 3-year BCR risk and 10-year CR risk similar to high-risk patients (Table). Conversely, high-risk patients with GPS≤ 40, who represented 63% of all high-risk patients, had a 3-year BCR risk and a 10-year CR risk similar to men with intermediate-risk disease. High-risk patients with GPS > 40 had 3-year BCR risk of almost 50% and 10-year CR risk of 35%. Conclusions: GPS appears to provide improved risk stratification for BCR and CR in AUA intermediate- and high-risk PCa. These findings require confirmation in an independent cohort of patients. [Table: see text]

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]

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

MP02-19 BIOMARKERS OF BIOCHEMICAL (BCR) AND CLINICAL RECURRENCE (CR) IN PROSTATE CANCER (PCA) FOLLOWING RADICAL PROSTATECTOMY (RP) – PERFORMANCE OF A 17-GENE GENOMIC PROSTATE SCORE (GPS) AND TESTS FOR PTEN LOSS.