Optimizing the clinical utility of PCA3 to diagnose prostate cancer in initial prostate biopsy

Role of PCA3 and SelectMDx in the optimization of active surveillance in prostate cancer

INTRODUCTION & OBJECTIVES

A not negligible percentage of patients included in active surveillance (AS) for low and very low risk prostate cancer (PCa) are reclassified in the confirmatory biopsy or have disease progression during follow-up. Our aim is to evaluate the role of PCA3 and SelectMDx, in an individual and combined way, in the prediction of pathological progression (PP) in a standard AS program.

MATERIALS & METHODS

Prospective and observational study comprised of 86 patients enrolled in an AS program from 2009 to 2019, with results for PCA3 and SelectMDx previous to PCa diagnosis or during their confirmatory period. Univariate and multivariate analysis were performed to correlate PCA3 and SelectMDx scores as well as clinical and pathological variables with PP-free survival (PPFS). The most reliable cut-offs for both biomarkers in the context of AS were defined.

RESULTS

SelectMDx showed statistically significant differences related to PPFS (HR 1.035, 95%CI: 1.012-1.057) (p = 0.002) with a C-index of 0.670 (95%CI: 0.529-0.810) and AUC of 0.714 (95%CI: 0.603-0.825) at 5 years. In our series, the most reliable cut-off point for SelectMDx was 5, with a sensitivity and specificity for PP of 69.8% and 67.4%, respectively. Same figure for PCA3 was 65, with a sensitivity and specificity for PP of 51.16% and 74.42%, respectively. The combination of both biomarkers did not improve the prediction of PP, C-index 0.630 (95%CI: 0.455-0.805).

CONCLUSIONS

In the context of low or very low risk PCa, SelectMDx > 5 predicted 5 years PP free survival with a moderate discrimination ability outperforming PCA3. The combination of both tests did not improved outcomes.

Role of PCA3 and SelectMDx in the optimization of active surveillance in prostate cancer

INTRODUCTION AND OBJECTIVES

A not negligible percentage of patients included in active surveillance (AS) for low and very low risk prostate cancer (PCa) are reclassified in the confirmatory biopsy or have disease progression during follow-up. Our aim is to evaluate the role of PCA3 and SelectMDx, in an individual and combined way, in the prediction of pathological progression (PP) in a standard AS program.

MATERIALS AND METHODS

Prospective and observational study comprised of 86 patients enrolled in an AS program from 2009 to 2019, with results for PCA3 and SelectMDx previous to PCa diagnosis or during their confirmatory period. Univariate and multivariate analysis were performed to correlate PCA3 and SelectMDx scores as well as clinical and pathological variables with PP-free survival (PPFS). The most reliable cut-offs for both biomarkers in the context of AS were defined.

RESULTS

SelectMDx showed statistically significant differences related to PPFS (HR: 1.035; 95%CI: 1.012-1.057) (P=.002) with a C-index of 0.670 (95%CI: 0.529-0.810) and AUC of 0.714 (95%CI: 0.603-0.825) at 5years. In our series, the most reliable cut-off point for SelectMDx was 5, with a sensitivity and specificity for PP of 69.8% and 67.4%, respectively. Same figure for PCA3 was 65, with a sensitivity and specificity for PP of 51.16% and 74.42%, respectively. The combination of both biomarkers did not improve the prediction of PP, C-index 0.630 (95%CI: 0.455-0.805).

CONCLUSIONS

In the context of low or very low risk PCa, SelectMDx >5 predicted 5years PP free survival with a moderate discrimination ability outperforming PCA3. The combination of both tests did not improved outcomes.

Diagnosis accuracy of PCA3 level in patients with prostate cancer: a systematic review with meta-analysis

BACKGROUND

The diagnostic value and suitability of prostate cancer antigen 3 (PCA3) for the detection of prostate cancer (PCa) have been inconsistent in previous studies. Thus, the aim of the present meta-analysis was performed to systematically evaluate the diagnostic value of PCA3 for PCa.

MATERIALS AND METHODS

A meta-analysis was performed to search relevant studies using online databases EMBASE, PubMed and Web of Science published until February 1st, 2019. Ultimately, 65 studies met the inclusion criteria for this meta-analysis with 8.139 cases and 14.116 controls. The sensitivity, specificity, positive likelihood ratios (LR+), negative likelihood ratios (LR-), and other measures of PCA3 were pooled and determined to evaluate the diagnostic rate of PCa by the random-effect model.

RESULTS

With PCA3, the pooled overall diagnostic sensitivity, specificity, LR+, LR-, and 95% confidence intervals (CIs) for predicting significant PCa were 0.68 (0.64-0.72), 0.72 (0.68-0.75), 2.41 (2.16-2.69), 0.44 (0.40-0.49), respectively. Besides, the summary diagnostic odds ratio (DOR) and 95% CIs for PCA3 was 5.44 (4.53-6.53). In addition, the area under summary receiver operating characteristic (sROC) curves and 95% CIs was 0.76 (0.72-0.79). The major design deficiencies of included studies were differential verification bias, and a lack of clear inclusion and exclusion criteria.

CONCLUSIONS

The results of this meta-analysis suggested that PCA3 was a non-invasive method with the acceptable sensitivity and specificity in the diagnosis of PCa, to distinguish between patients and healthy individuals. To validate the potential applicability of PCA3 in the diagnosis of PCa, more rigorous studies were needed to confirm these conclusions.

Validation of a 2-gene mRNA urine test for the detection of ≥GG2 prostate cancer in an opportunistic screening population

BACKGROUND

A 2-gene urine-based molecular test that targets messenger RNAs known to be overexpressed in aggressive prostate cancer (PCa) has been described as a helpful method for detecting clinically significant prostate cancer (grade group [GG] ≥2). We performed an external validation of this test in men undergoing initial prostate biopsy (Bx) within a Spanish opportunistic screening scenario.

METHODS

We analyzed archived samples from 492 men who underwent prostate Bx in an opportunistic screening scenario, with prostate-specific antigen (PSA) 3 to 10 ng/mL and/or suspicious digital rectal exploration (DRE) and without previous multi-parametric magnetic resonance imaging (mpMRI). Urinary biomarker measurements were combined with clinical risk factors to determine a risk score, and accuracy for GG ≥ 2 PCa detection was compared with PCA3, European randomized screening in prostate cancer (ERSPC), and prostate biopsy collaborative group (PBCG) risk calculators in a validation workup that included calibration, discrimination, and clinical utility analysis.

RESULTS

In our cohort, the detection rates for GG1 and GG ≥ 2 PCa were 20.3% and 14.0%, respectively. The median PSA level was 3.9 ng/mL and 13.4% of subjects had suspicious DRE findings. The median risk score for men with GG ≥ 2 PCa was 21 (interquartile range: 14-28), significantly higher than benign+GG1 PCa (10, 6-18), P < .001, achieving the highest area under the curve among the models tested, 0.749 (95% confidence interval: 0.690-0.807). The urine test was well-calibrated, while ERSPC showed a slight underestimation and PBCG a slight overestimation of risk. Assuming a GG2 non-detection rate of 11% without using mpMRI, use of the urinary biomarker-based clinical model could have helped avoid 37.2% of excess biopsies while delaying the diagnosis of eight patients (1.6% of the entire cohort) with GG ≥ 2 PCa.

CONCLUSIONS

In this first evaluation in an opportunistic screening population, the urinary biomarker-based test improved the detection of clinically significant PCa. Facing men with elevated PSA and/or suspicious DRE, it could be a useful tool to help avoid excess initial Bx and to identify patients most likely to benefit from Bx.

Are localized prostate cancer biomarkers useful in the clinical practice?

Prostate cancer presents itself in a heterogeneous way with both aggressive and indolent forms. Despite the controversy surrounding its use, prostate-specific antigen screening ultimately leads to a greater number of diagnosed patients. One of the biggest challenges in clinical practice is to select the right patients for biopsy and, among diagnosed patients, to differentiate tumors with an indolent course from those with an unfavorable prognosis, in order to determine the best therapeutic decision for each case, avoiding unnecessary interventions. Currently, several types of biomarkers are available for clinical use in patients with prostate cancer, which include blood-based (prostate-specific antigen, Prostate Health Index®, 4K score®); urine sample-based (PCA3, SelectMDx®, ExoDx Prostate IntelliScore®); and biopsy, transurethral resection, or radical prostatectomy tissue-based (ConfirmMDx®, Oncotype®, Prolaris®, Decipher®). The aim of this review is to provide an overview of the current state of evidence and to highlight recent advances in the evaluation and diagnosis of prostate cancer, with emphasis on biomarkers related to diagnosis and to prognostic evaluation of localized prostate cancer.

Spectrophotometric photodynamic diagnosis of prostate cancer cells excreted in voided urine using 5-aminolevulinic acid

To evaluate the feasibility of photodynamic diagnosis using 5-aminolevulinic acid (PDD-ALA) for detection of prostate cancer (PCa) cells in urine samples after prostate massage in patients who were suspected to have PCa. One hundred and eighty-nine patients with abnormal digital rectal examination and/or an elevated prostate-specific antigen (PSA) level who underwent initial prostate biopsy were recruited. After prostate massage, the first 60 mL of voided urine was collected. For PDD-ALA, 50 mL was used. The rest of collected urine was used for polymerase chain reaction (PCR) of PSA and glyceraldehyde 3-phosphate dehydrogenase (GAPDH). After incubation for 2 h, the intensity was measured at 635 nm under a 405-nm wavelength excitation. The results of PDD-ALA were compared with those of an initial transrectal ultrasound (TRUS)-guided prostate biopsy. Overall, 126/189 (67%) samples that showed bands of both PSA and GAPDH on PCR in urine samples were analyzed. The area under the curve, sensitivity, and specificity of PDD-ALA were 0.74, 77, and 67%, respectively. The value of PDD-ALA was significantly higher in patients with Gleason scores of 6 (p = 0.03), 7 (p = 0.005), and 8-10 (p = 0.0002) than in those with negative biopsy results. In the multivariate analysis, high PSA density, abnormal findings on TRUS, and a high value of PDD-ALA were significant markers for prediction of positive biopsy results. PDD-ALA was useful to predict positive biopsy results in patients who underwent initial prostate biopsy with suspected PCa. This PCa-detection method has potential for clinical use.

Whom to Biopsy: Prediagnostic Risk Stratification with Biomarkers, Nomograms, and Risk Calculators

This article describes markers used for prostate biopsy decisions, including prostrate-specific antigen (PSA), free PSA, the prostate health index, 4Kscore, PCA3, and ConfirmMDx. It also summarizes the use of nomograms combining multiple variables for prostate cancer detection.

The management of active surveillance in prostate cancer: validation of the Canary Prostate Active Surveillance Study risk calculator with the Spanish Urological Association Registry

The follow up of patients on active surveillance requires to repeat prostate biopsies. Predictive models that identify patients at low risk of progression or reclassification are essential to reduce the number of unnecessary biopsies. The aim of this study is to validate the Prostate Active Surveillance Study risk calculator (PASS-RC) in the multicentric Spanish Urological Association Registry of patients on active surveillance (AS), from common clinical practice.

PCA3 as a second-line biomarker in a prospective controlled randomized opportunistic prostate cancer screening programme

OBJECTIVES

PCA3 performance as a single second line biomarker is compared to the European Randomised Study of Screening for Prostate Cancer risk calculator model 3 (ERSPC RC-3) in an opportunistic screening in prostate cancer (PCa).

MATERIAL AND METHODS

5,199 men, aged 40-75y, underwent prostate-specific antigen (PSA) screening and digital rectal examination (DRE). Men with a normal DRE and PSA ≥3ng/ml had a PCA3 test done. All men with PCA3 ≥35 underwent an initial biopsy (IBx) -12 cores-. Men with PCA3 <35 were randomized 1:1 to either IBx or observation. We compared them to those obtained with ERSPC RC-3.

RESULTS

PCA3 test was performed on 838 men (16.1%). In PCA3(+) and PCA3(-) groups, global PCa detection rates were 40.9% and 14.7% with a median follow-up (FU) of 21.7 months (P<.001). In the PCA3(+) arm (n=301, 35.9%), PCa was identified in 115 men at IBx (38.2%). In the randomized arm, 256 underwent IBx and PCa was found in 46 (18.0%) (P<.001). The biopsy-sparing potential would have been 64.1% as opposed to 76.6% if we had used ERSPC RC-3. However, the estimated false negative cases for HGPCa would have been reduced by 37.1% (89 to 56 patients). Moreover, if we had applied PCA3-35 to avoid IBx, 14.7% PCa and 9.1% of clinical significant PCa patients would not have been diagnosed during this FU.

CONCLUSIONS

When PCA3-35 is used as a second-line biomarker when PSA ≥3ng/ml and DRE is normal, IBx could be avoided in 12.5% less than if ERSPC RC-3 is used and would reduce the false negative cases by 36.2%. At a FU of 21.7 months, this dual protocol would miss 9.1% of clinically significant PCa, so strict FU is mandatory with established biopsy criteria based on PSA and DRE in cases with PCA3 <35.

The role of prostate cancer biomarkers in undiagnosed men

PURPOSE OF REVIEW

This article intends to review biomarkers derived from blood, urine, and tissue that can aid in the diagnosis of prostate cancer (PCa).

RECENT FINDINGS

PCa screening requires tools that complement prostate-specific antigen (PSA) with a higher specificity for clinically significant disease. Novel blood biomarkers, such as the Prostate Health Index (phi) and 4Kscore, utilize isoforms of PSA to more accurately predict high-grade PCa than traditional tools such as PSA and the percentage free-to-total PSA. Several gene products associated with PCa can be detected in the urine through commercially available assays. PCa antigen 3 (PCA3), though approved for repeat biopsy decisions, appears inferior to other biomarkers such as phi for identifying aggressive disease. However, combinations of PCA3 with other urine assays have shown promising results. One tissue-based hypermethylation test, named ConfirmMDx, can also be used to determine the need for repeat biopsy in men with a prior negative biopsy.

SUMMARY

Several biomarkers have been developed to aid in the screening and diagnosis of PCa. Such tests are often indicated in men with moderately elevated PSA or history of a prior negative biopsy. Their use facilitates reduction of unnecessary biopsies without sacrificing the early diagnosis of clinically significant PCa.

External validation of a PCA-3-based nomogram for predicting prostate cancer and high-grade cancer on initial prostate biopsy

INTRODUCTION

The aim of this study was to externally validate a previously developed PCA3-based nomogram for the prediction of prostate cancer (PCa) and high-grade (intermediate and/or high-grade) prostate cancer (HGPCa) at the time of initial prostate biopsy.

METHODS

A retrospective review was performed on a cohort of 336 men from a large urban academic medical center. All men had serum PSA <20 ng/ml and underwent initial transrectal ultrasound-guided prostate biopsy with at least 10 cores sampling for suspicious exam and/or elevated PSA. Covariates were collected for the nomogram and included age, ethnicity, family history (FH) of PCa, PSA at diagnosis, PCA3, total prostate volume (TPV), and abnormal finding on digital rectal exam (DRE). These variables were used to test the accuracy (concordance index) and calibration of a previously published PCA3 nomogram.

RESULTS

Biopsy confirms PCa and HGPCa in 51.0% and 30.4% of validation patients, respectively. This differed from the original cohort in that it had significantly more PCa and HGPCA (51% vs. 44%, P = 0.019; and 30.4% vs. 19.1%, P < 0.001). Despite the differences in PCa detection the concordance index was 75% and 77% for overall PCa and HGPCa, respectively. Calibration for overall PCa was good.

CONCLUSIONS

This represents the first external validation of a PCA3-based prostate cancer predictive nomogram in a North American population. Prostate 76:1019-1023, 2016. © 2016 Wiley Periodicals, Inc.