Association of [-2]proPSA with biopsy reclassification during active surveillance for prostate cancer

Feasibility for active surveillance in biopsy Gleason 3 + 4 prostate cancer: an Australian radical prostatectomy cohort

OBJECTIVE

To examine the feasibility of active surveillance for low volume Gleason sum (GS) 3 + 4 disease compared to GS 3 + 3 disease.

PATIENTS AND METHODS

Retrospective review of 929 patients, with biopsy proven GS 3 + 3 and 3 + 4 PCa, undergoing upfront radical prostatectomy (RP) was performed. Suitability for AS was adapted from protocols by Royal Marsden Hospital, University of Toronto, and PRIAS by allowing Gleason 3 + 4 disease. The outcomes assessed were adverse pathology at RP (upgrading ≥GS 4 + 3 and/or upstaging ≥pT3) and biochemical recurrence (BCR) after RP.

RESULTS

Adverse pathology at RP was compared between GS 3 + 3 vs 3 + 4 groups. When selecting patients using Royal Marsden (n = 714) or University of Toronto (n = 699) protocols, there was statistically significantly more adverse pathology at RP in GS 3 + 4 group (21% vs 31%, P = 0.0028 and 19% vs 33%, P=<0.001 respectively). Using the more stringent PRIAS protocol (n = 198), there was no statistical significant difference in groups. There was no difference in BCR survival between biopsy GS 3 + 3 and 3 + 4 groups, regardless of which AS protocol assessed. Pre-operative PSA and clinical staging were the predictors for BCR.

CONCLUSION

Presence of Gleason 3 + 4 at biopsy, when compared to 3 + 3, increases the risk of adverse pathology being present at radical prostatectomy for less stringent selection criteria. When considering AS, a stricter protocol such as PRIAS, limiting PSA density and number of positive cores to ≤2, appears to decrease the risk of adverse pathology. No differences in BCR were seen between biopsy 3 + 3 and 3 + 4 disease, regardless of AS selection criteria.

Active surveillance monitoring: the role of novel biomarkers and imaging

“CANCER” is a disease state that leads to progressive illness that is uniformly fatal without treatment. Hippocrates invoked the Greek word karkinos, or “crab,” to describe tumors he observed. For centuries, “CANCER” remained a disease that was recognized primarily in its locally advanced or metastatic stage, when it was almost uniformly fatal.

Active surveillance for prostate cancer: current evidence and contemporary state of practice

Prostate cancer remains one of the most commonly diagnosed malignancies worldwide. Early diagnosis and curative treatment seem to improve survival in men with unfavourable-risk cancers, but significant concerns exist regarding the overdiagnosis and overtreatment of men with lower-risk cancers. To this end, active surveillance (AS) has emerged as a primary management strategy in men with favourable-risk disease, and contemporary data suggest that use of AS has increased worldwide. Although published surveillance cohorts differ by protocol, reported rates of metastatic disease and prostate-cancer-specific mortality are exceedingly low in the intermediate term (5-10 years). Such outcomes seem to be closely associated with programme-specific criteria for selection, monitoring, and intervention, suggesting that AS--like other management strategies--could be individualized based on the level of risk acceptable to patients in light of their personal preferences. Additional data are needed to better establish the risks associated with AS and to identify patient-specific characteristics that could modify prognosis.

Risk stratification of prostate cancer in the modern era

PURPOSE OF REVIEW

Novel tools have become available to the practicing urologist in recent years that endeavor to improve on commonly utilized prostate cancer (PCa) risk-stratification techniques. In this review, we provide an overview of these modalities in the context of active surveillance.

RECENT FINDINGS

Multiparametric MRI (MP-MRI) has a rapidly growing body of evidence that suggests it provides the necessary sensitivity and negative predictive value to rule out clinically significant disease. MRI-guided targeted biopsy has the potential to improve detection of clinically significant cancers and for rebiopsy of patients with continued suspicion for PCa. Prostate-specific antigen isoforms and Prostate Health Index outperform PSA alone and improve risk stratification when combined with the established criteria, but need further prospective studies using template and MRI-targeted biopsies. Urinary biomarkers tend to fall short in predicting adverse pathology when used alone, but improve risk stratification when used in conjunction and with the established criteria. Finally, tissue biomarkers and gene assays allow patient-specific molecular and genetic characterization of cancer phenotype, showing significant promise in predicting adverse pathology, and in some cases have already been incorporated into and altered clinical practice.

SUMMARY

These novel modalities show remarkable promise in improving the risk stratification of patients with PCa, and as the body of evidence grows will likely become incorporated into major oncologic guidelines and standard urologic practice. Further prospective clinical studies are needed, as well as analysis of cost-effectiveness.

Comprehensive assessment for novel prostate cancer markers in the prostate-specific antigen era: focusing on Asians and Asian countries

We reviewed the current evidence for three novel prostate tumor markers (PCA3, TMPRSS2:ERG and proPSA) that have been recently reported predominantly in Western countries. We focus our attention on Asian men in both clinical and basic research studies. There have been no reports on the clinical usefulness of these three markers for Asians living in Western countries. In Asian countries, evidence for the clinical usefulness of PCA3 and proPSA-related indices including Prostate Health Index is being accumulated, mainly in Japan. The process for how a novel marker is approved in the clinical setting is also discussed.

The Prostate Health Index: Its Utility in Prostate Cancer Detection

The Prostate Health Index is a Food and Drug Administration-approved blood test combining total, free, and [-2]pro prostate-specific antigen with greater specificity than free and total prostate-specific antigen for clinically significant prostate cancer. This article reviews the evidence on the performance of the Prostate Health Index to predict prostate biopsy outcome, its incorporation into multivariable risk-assessment tools, and its ability to predict prognosis after conservative management or prostate cancer treatment.

Biomarkers in localized prostate cancer

Biomarkers can improve prostate cancer diagnosis and treatment. Accuracy of prostate-specific antigen (PSA) for early diagnosis of prostate cancer is not satisfactory, as it is an organ- but not cancer-specific biomarker, and it can be improved by using models that incorporate PSA along with other test results, such as prostate cancer antigen 3, the molecular forms of PSA (proPSA, benign PSA and intact PSA), as well as kallikreins. Recent reports suggest that new tools may be provided by metabolomic studies as shown by preliminary data on sarcosine. Additional molecular biomarkers have been identified by the use of genomics, proteomics and metabolomics. We review the most relevant biomarkers for early diagnosis and management of localized prostate cancer.

Active Surveillance of Prostate Cancer: Use, Outcomes, Imaging, and Diagnostic Tools

Active surveillance (AS) has emerged as a standard management option for men with very low-risk and low-risk prostate cancer, and contemporary data indicate that use of AS is increasing in the United States and abroad. In the favorable-risk population, reports from multiple prospective cohorts indicate a less than 1% likelihood of metastatic disease and prostate cancer-specific mortality over intermediate-term follow-up (median 5-6 years). Higher-risk men participating in AS appear to be at increased risk of adverse outcomes, but these populations have not been adequately studied to this point. Although monitoring on AS largely relies on serial prostate biopsy, a procedure associated with considerable morbidity, there is a need for improved diagnostic tools for patient selection and monitoring. Revisions from the 2014 International Society of Urologic Pathology consensus conference have yielded a more intuitive reporting system and detailed reporting of low-intermediate grade tumors, which should facilitate the practice of AS. Meanwhile, emerging modalities such as multiparametric magnetic resonance imaging and tissue-based molecular testing have shown prognostic value in some populations. At this time, however, these instruments have not been sufficiently studied to consider their routine, standardized use in the AS setting. Future studies should seek to identify those platforms most informative in the AS population and propose a strategy by which promising diagnostic tools can be safely and efficiently incorporated into clinical practice.

Biomarkers for prostate cancer: present challenges and future opportunities

Prostate cancer (PCa) has variable biological potential with multiple treatment options. A more personalized approach, therefore, is needed to better define men at higher risk of developing PCa, discriminate indolent from aggressive disease and improve risk stratification after treatment by predicting the likelihood of progression. This may improve clinical decision-making regarding management, improve selection for active surveillance protocols and minimize morbidity from treatment. Discovery of new biomarkers associated with prostate carcinogenesis present an opportunity to provide patients with novel genetic signatures to better understand their risk of developing PCa and help forecast their clinical course. In this review, we examine the current literature evaluating biomarkers in PCa. We also address current limitations and present several ideas for future studies.

Prostate Health Index (PHI) Predicts High-stage Pathology in African American Men

OBJECTIVE

To evaluate the association between the Prostate Health Index (PHI) and adverse pathology in a cohort of African American (AA) men undergoing radical prostatectomy.

MATERIALS AND METHODS

Eighty AA men with prostate-specific antigen (PSA) of 2-10 ng/mL underwent measurement of PSA, free PSA (fPSA), and p2PSA prior to radical prostatectomy. PHI was calculated as [(p2PSA/fPSA) × (PSA)(½)]. Biomarker association with pT3 disease was assessed using logistic regression, and covariates were added to a baseline multivariable model including digital rectal examination. Biomarker ability to predict pT3 disease was measured using the area under the receiver operator characteristic curve.

RESULTS

Sixteen men (20%) demonstrated pT3 disease on final pathology. Mean age, PSA, and %fPSA were similar in men with and without pT3 disease (all P  >  .05), whereas PHI was significantly greater in men with pT3 disease (mean 57.2 vs 46.6, P  =  .04). Addition of PHI to the baseline multivariable model improved discriminative ability by 12.9% (P  =. .04) and yielded greater diagnostic accuracy than models, including other individual biomarkers.

CONCLUSION

In AA men with PSA of 2-10 ng/mL, PHI was predictive of pT3 prostate cancer and may help to identify men at increased risk of adverse pathology. Additional studies are needed to substantiate these findings and identify appropriate thresholds for clinical use.

Predicting Pathological Features at Radical Prostatectomy in Patients with Prostate Cancer Eligible for Active Surveillance by Multiparametric Magnetic Resonance Imaging

PURPOSE

The aim of this study was to investigate the prognostic performance of multiparametric magnetic resonance imaging (mpMRI) and Prostate Imaging Reporting and Data System (PIRADS) score in predicting pathologic features in a cohort of patients eligible for active surveillance who underwent radical prostatectomy.

METHODS

A total of 223 patients who fulfilled the criteria for "Prostate Cancer Research International: Active Surveillance", were included. Mp-1.5 Tesla MRI examination staging with endorectal coil was performed at least 6-8 weeks after TRUS-guided biopsy. In all patients, the likelihood of the presence of cancer was assigned using PIRADS score between 1 and 5. Outcomes of interest were: Gleason score upgrading, extra capsular extension (ECE), unfavorable prognosis (occurrence of both upgrading and ECE), large tumor volume (≥ 0.5 ml), and seminal vesicle invasion (SVI). Receiver Operating Characteristic (ROC) curves and Decision Curve Analyses (DCA) were performed for models with and without inclusion of PIRADS score.

RESULTS

Multivariate analysis demonstrated the association of PIRADS score with upgrading (P < 0.0001), ECE (P < 0.0001), unfavorable prognosis (P < 0.0001), and large tumor volume (P = 0.002). ROC curves and DCA showed that models including PIRADS score resulted in greater net benefit for almost all the outcomes of interest, with the only exception of SVI.

CONCLUSIONS

mpMRI and PIRADS scoring are feasible tools in clinical setting and could be used as decision-support systems for a more accurate selection of patients eligible for AS.

Potential Utility of Novel Biomarkers in Active Surveillance of Low-Risk Prostate Cancer

Active surveillance (AS) is now an accepted management strategy for men with low-risk localized prostate cancer (PCa). However, detecting disease progression in a patient selected for AS remains a challenge. It is crucial to know what will serve as the best parameter to correctly identify tumors that progress to a more aggressive phenotype so as not to miss the window of curability. Several biomarkers are now being actively investigated as novel tools to improve PCa risk assessments. To date, several serum, urinary, and tissue biomarkers have shown promising prognostic value. %[-2]proPSA and PHI showed improved predictive value for an unfavorable biopsy conversion at annual surveillance biopsy in the AS program. PCA3 and TMPRSS2:ERG had additional independent predictive value for the prediction of PCa detection and progression, although PCA3 was limited in predicting aggressive cancer. Other tissue biomarkers also showed promising ability to predict disease progression. Although several of these novel biomarkers have an improved predictive accuracy that is better than classical parameters, there is still a need for further well-designed, large, multicenter, prospective trials to avoid common bias and clinical validation.

PHI and PCA3 improve the prognostic performance of PRIAS and Epstein criteria in predicting insignificant prostate cancer in men eligible for active surveillance

PURPOSE

To assess the performance of prostate health index (PHI) and prostate cancer antigen 3 (PCA3) when added to the PRIAS or Epstein criteria in predicting the presence of pathologically insignificant prostate cancer (IPCa) in patients who underwent radical prostatectomy (RP) but eligible for active surveillance (AS).

METHODS

An observational retrospective study was performed in 188 PCa patients treated with laparoscopic or robot-assisted RP but eligible for AS according to Epstein or PRIAS criteria. Blood and urinary specimens were collected before initial prostate biopsy for PHI and PCA3 measurements. Multivariate logistic regression analyses and decision curve analysis were carried out to identify predictors of IPCa using the updated ERSPC definition.

RESULTS

At the multivariate analyses, the inclusion of both PCA3 and PHI significantly increased the accuracy of the Epstein multivariate model in predicting IPCa with an increase of 17 % (AUC = 0.77) and of 32 % (AUC = 0.92), respectively. The inclusion of both PCA3 and PHI also increased the predictive accuracy of the PRIAS multivariate model with an increase of 29 % (AUC = 0.87) and of 39 % (AUC = 0.97), respectively. DCA revealed that the multivariable models with the addition of PHI or PCA3 showed a greater net benefit and performed better than the reference models. In a direct comparison, PHI outperformed PCA3 performance resulting in higher net benefit.

CONCLUSIONS

In a same cohort of patients eligible for AS, the addition of PHI and PCA3 to Epstein or PRIAS models improved their prognostic performance. PHI resulted in greater net benefit in predicting IPCa compared to PCA3.

Active surveillance for prostate cancer: when to recommend delayed intervention

There are no agreed upon guidelines for placing patients on active surveillance (AS). Therefore, there are no absolute criteria for taking patients off AS and when to recommend treatment. The criteria used to define progression are currently based on prostate specific antigen (PSA) kinetics, biopsy reclassification, and change in clinical stage. Multiple studies have evaluated predictors of progression such as PSA, PSA density (PSAD), prostate volume, core positivity, and visible lesion on multiparametric magnetic resonance imaging (mpMRI). Furthermore, published nomograms designed to predict indolent prostate cancer do not perform well when used to predict progression. Newer biomarkers have also not performed well to predict progression. These findings highlight that clinical and pathologic variables are not enough to identify patients that will progress while on AS. In the future, with the use of imaging, biomarkers, and gene expression assays, we should be better equipped to diagnose/stage prostate cancer and to distinguish between insignificant and significant disease.

Expectant management for men with early stage prostate cancer

Since the dissemination of prostate-specific antigen screening, most men with prostate cancer are now diagnosed with localized, low-risk prostate cancer that is unlikely to be lethal. Nevertheless, nearly all of these men undergo primary treatment with surgery or radiation, placing them at risk for longstanding side effects, including erectile dysfunction and impaired urinary function. Active surveillance and other observational strategies (ie, expectant management) have produced excellent long-term disease-specific survival and minimal morbidity for men with prostate cancer. Despite this, expectant management remains underused for men with localized prostate cancer. In this review, various approaches to the expectant management of men with prostate cancer are summarized, including watchful waiting and active surveillance strategies. Contemporary cancer-specific and health care quality-of-life outcomes are described for each of these approaches. Finally, contemporary patterns of use, potential disparities in care, and ongoing research and controversies surrounding expectant management of men with localized prostate cancer are discussed.

The percentage of prostate-specific antigen (PSA) isoform [-2]proPSA and the Prostate Health Index improve the diagnostic accuracy for clinically relevant prostate cancer at initial and repeat biopsy compared with total PSA and percentage free PSA in men aged ≤65 years

OBJECTIVES

To prospectively test the diagnostic accuracy of the percentage of prostate specific antigen (PSA) isoform [-2]proPSA (%p2PSA) and the Prostate Health Index (PHI), and to determine their role for discrimination between significant and insignificant prostate cancer at initial and repeat prostate biopsy in men aged ≤65 years.

PATIENTS AND METHODS

The diagnostic performance of %p2PSA and PHI were evaluated in a multicentre study. In all, 769 men aged ≤65 years scheduled for initial or repeat prostate biopsy were recruited in four sites based on a total PSA (t-PSA) level of 1.6-8.0 ng/mL World Health Organization (WHO) calibrated (2-10 ng/mL Hybritech-calibrated). Serum samples were measured for the concentration of t-PSA, free PSA (f-PSA) and p2PSA with Beckman Coulter immunoassays on Access-2 or DxI800 instruments. PHI was calculated as (p2PSA/f-PSA × √t-PSA). Uni- and multivariable logistic regression models and an artificial neural network (ANN) were complemented by decision curve analysis (DCA).

RESULTS

In univariate analysis %p2PSA and PHI were the best predictors of prostate cancer detection in all patients (area under the curve [AUC] 0.72 and 0.73, respectively), at initial (AUC 0.67 and 0.69) and repeat biopsy (AUC 0.74 and 0.74). t-PSA and %f-PSA performed less accurately for all patients (AUC 0.54 and 0.62). For detection of significant prostate cancer (based on Prostate Cancer Research International Active Surveillance [PRIAS] criteria) the %p2PSA and PHI equally demonstrated best performance (AUC 0.70 and 0.73) compared with t-PSA and %f-PSA (AUC 0.54 and 0.59). In multivariate analysis PHI we added to a base model of age, prostate volume, digital rectal examination, t-PSA and %f-PSA. PHI was strongest in predicting prostate cancer in all patients, at initial and repeat biopsy and for significant prostate cancer (AUC 0.73, 0.68, 0.78 and 0.72, respectively). In DCA for all patients the ANN showed the broadest threshold probability and best net benefit. PHI as single parameter and the base model + PHI were equivalent with threshold probability and net benefit nearing those of the ANN. For significant cancers the ANN was the strongest parameter in DCA.

CONCLUSION

The present multicentre study showed that %p2PSA and PHI have a superior diagnostic performance for detecting prostate cancer in the PSA range of 1.6-8.0 ng/mL compared with t-PSA and %f-PSA at initial and repeat biopsy and for predicting significant prostate cancer in men aged ≤65 years. They are equally superior for counselling patients before biopsy.

Prognostic accuracy of Prostate Health Index and urinary Prostate Cancer Antigen 3 in predicting pathologic features after radical prostatectomy

OBJECTIVE

To compare the prognostic accuracy of Prostate Health Index (PHI) and Prostate Cancer Antigen 3 in predicting pathologic features in a cohort of patients who underwent radical prostatectomy (RP) for prostate cancer (PCa).

METHODS AND MATERIALS

We evaluated 156 patients with biopsy-proven, clinically localized PCa who underwent RP between January 2013 and December 2013 at 2 tertiary care institutions. Blood and urinary specimens were collected before initial prostate biopsy for [-2] pro-prostate-specific antigen (PSA), its derivates, and PCA3 measurements. Univariate and multivariate logistic regression analyses were carried out to determine the variables that were potentially predictive of tumor volume > 0.5 ml, pathologic Gleason sum ≥ 7, pathologically confirmed significant PCa, extracapsular extension, and seminal vesicles invasions.

RESULTS

On multivariate analyses and after bootstrapping with 1,000 resampled data, the inclusion of PHI significantly increased the accuracy of a baseline multivariate model, which included patient age, total PSA, free PSA, rate of positive cores, clinical stage, prostate volume, body mass index, and biopsy Gleason score (GS), in predicting the study outcomes. Particularly, to predict tumor volume > 0.5, the addition of PHI to the baseline model significantly increased predictive accuracy by 7.9% (area under the receiver operating characteristics curve [AUC] = 89.3 vs. 97.2, P>0.05), whereas PCA3 did not lead to a significant increase. Although both PHI and PCA3 significantly improved predictive accuracy to predict extracapsular extension compared with the baseline model, achieving independent predictor status (all P's < 0.01), only PHI led to a significant improvement in the prediction of seminal vesicles invasions (AUC = 92.2, P < 0.05 with a gain of 3.6%). In the subset of patients with GS ≤ 6, PHI significantly improved predictive accuracy by 7.6% compared with the baseline model (AUC = 89.7 vs. 97.3) to predict pathologically confirmed significant PCa and by 5.9% compared with the baseline model (AUC = 83.1 vs. 89.0) to predict pathologic GS ≥ 7. For these outcomes, PCA3 did not add incremental predictive value.

CONCLUSIONS

In a cohort of patients who underwent RP, PHI is significantly better than PCA3 in the ability to predict the presence of both more aggressive and extended PCa.

Clinical performance of serum [-2]proPSA derivatives, %p2PSA and PHI, in the detection and management of prostate cancer

Prostate-specific antigen (PSA) has been widely used as a serum marker for prostate cancer (PCa) screening or progression monitoring, which dramatically increased rate of early detection while significantly reduced PCa-specific mortality. However, a number of limitations of PSA have been noticed. Low specificity of PSA may lead to overtreatment in men who presenting with a total PSA (tPSA) level of < 10 ng/mL. As a type of free PSA (fPSA), [-2]proPSA is differentially expressed in peripheral zone of prostate gland and found to be elevated in serum of men with PCa. Two p2PSA-based derivatives, prostate health index (PHI) and %p2PSA, which were defined as [(p2PSA/fPSA) × √ tPSA] and [(p2PSA/fPSA) × 100] respectively, have been suggested to be increased in PCa and can better distinguish PCa from benign prostatic diseases than tPSA or fPSA. We performed a systematic review of the available scientific evidences to evaluate the potentials of %p2PSA and PHI in clinical application. Mounting evidences suggested that both %p2PSA and PHI possess higher area under the ROC curve (AUC) and better specificity at a high sensitivity for PCa detection when compare with tPSA and %fPSA. It indicated that measurements of %p2PSA and PHI significantly improved the accuracy of PCa detection and diminished unnecessary biopsies. Furthermore, elevations of %p2PSA and PHI are related to more aggressive diseases. %p2PSA and PHI might be helpful in reducing overtreatment on indolent cases or assessing the progression of PCa in men who undergo active surveillance. Further studies are needed before being applied in routine clinical practice.

Circulating biomarkers for discriminating indolent from aggressive disease in prostate cancer active surveillance

PURPOSE OF REVIEW

To review research on the use of circulating biomarkers to predict unfavorable tumor pathology in the setting of active surveillance, or in clinical contexts that are informative for active surveillance, such as men with low-risk prostate cancer evaluated for upgrading or upstaging at surgery.

RECENT FINDINGS

Biomarkers have been evaluated in serum, plasma, urine, and expressed prostatic secretions. Only a small number of biomarkers have been evaluated in multiple studies: %free prostate-specific antigen (PSA), PSA velocity, PSA doubling time, proPSA, PCA3, TMPRSS2-ERG. Single studies with relevance to active surveillance have evaluated microRNAs, circulating tumor cells, and exosomes. The most consistent significant associations with unfavorable tumor pathology have been with %free PSA. Associations with [-2]proPSA and Prostate Health Index have also been consistent; however, three of four studies come from the same active surveillance patient cohort.

SUMMARY

Circulating biomarkers represent a promising approach to identify men with apparently low-risk biopsy pathology, but who harbor potentially aggressive tumors unsuitable for active surveillance. Research is still at an early stage; existing biomarkers need rigorous validation with consistent methodology, and additional biomarkers need to be evaluated. Successful clinical translation would reduce the frequency of surveillance biopsies, and may enhance acceptance of active surveillance.

The prostate health index selectively identifies clinically significant prostate cancer

PURPOSE

The Prostate Health Index (phi) is a new test combining total, free and [-2]proPSA into a single score. It was recently approved by the FDA and is now commercially available in the U.S., Europe and Australia. We investigate whether phi improves specificity for detecting clinically significant prostate cancer and can help reduce prostate cancer over diagnosis.

MATERIALS AND METHODS

From a multicenter prospective trial we identified 658 men age 50 years or older with prostate specific antigen 4 to 10 ng/ml and normal digital rectal examination who underwent prostate biopsy. In this population we compared the performance of prostate specific antigen, % free prostate specific antigen, [-2]proPSA and phi to predict biopsy results and, specifically, the presence of clinically significant prostate cancer using multiple criteria.

RESULTS

The Prostate Health Index was significantly higher in men with Gleason 7 or greater and "Epstein significant" cancer. On receiver operating characteristic analysis phi had the highest AUC for overall prostate cancer (AUCs phi 0.708, percent free prostate specific antigen 0.648, [-2]proPSA 0.550 and prostate specific antigen 0.516), Gleason 7 or greater (AUCs phi 0.707, percent free prostate specific antigen 0.661, [-2]proPSA 0.558, prostate specific antigen 0.551) and significant prostate cancer (AUCs phi 0.698, percent free prostate specific antigen 0.654, [-2]proPSA 0.550, prostate specific antigen 0.549). At the 90% sensitivity cut point for phi (a score less than 28.6) 30.1% of patients could have been spared an unnecessary biopsy for benign disease or insignificant prostate cancer compared to 21.7% using percent free prostate specific antigen.

CONCLUSIONS

The new phi test outperforms its individual components of total, free and [-2]proPSA for the identification of clinically significant prostate cancer. Phi may be useful as part of a multivariable approach to reduce prostate biopsies and over diagnosis.

Active surveillance for prostate cancer: a systematic review of clinicopathologic variables and biomarkers for risk stratification

CONTEXT

Active surveillance (AS) is an important strategy to reduce prostate cancer overtreatment. However, the optimal criteria for eligibility and predictors of progression while on AS are debated.

OBJECTIVE

To review primary data on markers, genetic factors, and risk stratification for patient selection and predictors of progression during AS.

EVIDENCE ACQUISITION

Electronic searches were conducted in PubMed, Embase, and the Cochrane Central Register of Controlled Trials (CENTRAL) from inception to April 2014 for original articles on biomarkers and risk stratification for AS.

EVIDENCE SYNTHESIS

Patient factors associated with AS outcomes in some studies include age, race, and family history. Multiple studies provide consistent evidence that a lower percentage of free prostate-specific antigen (PSA), a higher Prostate Health Index (PHI), a higher PSA density (PSAD), and greater biopsy core involvement at baseline predict a greater risk of progression. During follow-up, serial measurements of PHI and PSAD, as well as repeat biopsy results, predict later biopsy progression. While some studies have suggested a univariate relationship between urinary prostate cancer antigen 3 (PCA3) and transmembrane protease, serine 2-v-ets avian erythroblastosis virus E26 oncogene homolog gene fusion (TMPRSS2:ERG) with adverse biopsy features, these markers have not been consistently shown to independently predict AS outcomes. No conclusive data support the use of genetic tests in AS. Limitations of these studies include heterogeneous definitions of progression and limited follow-up.

CONCLUSIONS

There is a growing body of literature on patient characteristics, biopsy features, and biomarkers with potential utility in AS. More data are needed on practical applications such as combining these tests into multivariable clinical algorithms and long-term outcomes to further improve AS in the future.

PATIENT SUMMARY

Several PSA-based tests (free PSA, PHI, PSAD) and the extent of cancer on biopsy can help to stratify the risk of progression during active surveillance. Investigation of several other markers is under way.

Preoperative Prostate-specific Antigen Isoform p2PSA and Its Derivatives, %p2PSA and Prostate Health Index, Predict Pathologic Outcomes in Patients Undergoing Radical Prostatectomy for Prostate Cancer: Results from a Multicentric European Prospective Study

BACKGROUND

Currently available predictive models fail to assist clinical decision making in prostate cancer (PCa) patients who are potential candidates for radical prostatectomy (RP). New biomarkers would be welcome.

OBJECTIVE

To test the hypothesis that prostate-specific antigen (PSA) isoform p2PSA and its derivatives, percentage of p2PSA to free PSA (%p2PSA) and the Prostate Health Index (PHI), predict PCa characteristics at final pathology.

DESIGN, SETTING, AND PARTICIPANTS

An observational prospective multicentre European study was performed in 489 consecutive PCa patients treated with RP. Total PSA (tPSA), free PSA (fPSA), and p2PSA levels were determined. The %fPSA [(fPSA / tPSA) × 100], %p2PSA [(p2PSA pg/ml) / (fPSA ng/ml × 1000) × 100], and PHI [(p2PSA / fPSA) × √tPSA] were calculated.

INTERVENTION

Open or robot-assisted RP.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Logistic regression models were fitted to test the predictors of pT3 stage and/or pathologic Gleason score (GS) ≥7 and to determine their predictive accuracy. The base multivariable model included tPSA, digital rectal examination, biopsy GS, and percentage of positive biopsy cores. Decision curve analysis provided an estimate of the net benefit obtained using p2PSA, %p2PSA, or PHI.

RESULTS AND LIMITATIONS

Overall, 344 patients (70%) were affected by pT3 disease or pathologic GS ≥7; pT3 disease and pathologic GS ≥7 were present in 126 patients (26%). At univariable analysis, p2PSA, %p2PSA, and PHI were significant predictors of pT3 disease and/or pathologic GS ≥7 (all p ≤ 0.001). The inclusion of PHI significantly increased the accuracy of the base multivariable model by 2.3% (p=0.003) and 2.4% (p=0.01) for the prediction of pT3 disease and/or pathologic GS ≥7, respectively. However, at decision curve analysis, models including PHI did not show evidence of a greater clinical net benefit.

CONCLUSIONS

Both %p2PSA and PHI are significant predictors of unfavourable PCa characteristics at final pathology; however, %p2PSA and PHI did not provide a greater net benefit for clinical decision making.

PATIENT SUMMARY

Prostate-specific antigen (PSA) isoform p2PSA and its derivatives, percentage of p2PSA to free PSA and the Prostate Health Index, are associated with adverse characteristics of prostate cancer; however, these biomarkers provided only a slight net benefit for clinical decision making.

Implementation of PSA-based active surveillance in prostate cancer

Prostate cancer screening had led to the diagnosis of a large proportion of localized and low-risk disease. Many of these cancer cases are believed to be indolent and would not be clinically perceived in the absence of screening. In addition to that, the wide use of active treatment has exposed these patients to treatment-related quality-of-life impact. In this setting active surveillance as a way of deferring active treatment and reserving such treatment to cases of disease progression only has gained interest. PSA has been widely used to identify patients eligible for active surveillance and also for disease monitoring. The goal of this review was to describe the place of PSA in the monitoring of patients under active surveillance based on the existing studies and to discuss the importance of PSA in light of other existing or emerging tools to monitor prostate cancer in active surveillance.

Clinical use of [-2]proPSA (p2PSA) and its derivatives (%p2PSA and Prostate Health Index) for the detection of prostate cancer: a review of the literature

Prostate-specific antigen (PSA) is recognized as an organ-specific marker with low specificity and sensitivity in discriminating prostate cancer (PCa) from other benign conditions, such as prostatic hyperplasia or chronic prostatitis. Thus, in the case of clinical suspicion, a PCa diagnosis cannot be made without a prostate biopsy. [-2]proPSA (p2PSA), a precursor of PSA, has been investigated as a new marker to accurately detect PCa. The aim of this systematic review was to discuss the available literature regarding the clinical validity and utility of p2PSA and its derivatives, p2PSA/fPSA (%p2PSA) and the Prostate Health Index (PHI). A systematic search of the PubMed and Scopus electronic databases was performed in accordance with the PRISMA statement (http://www.prisma-statement.org), considering the time period from January 1990 to January 2014 and using the following search terms: proprostate specific antigen, proenzyme PSA, proPSA, [-2]proPSA, p2PSA, Prostate Health Index, and PHI. To date, 115 studies have been published, but only 35 were considered for the qualitative analysis. These studies suggested that p2PSA is the most cancer-specific form of PSA, being preferentially expressed in PCa tissue and being significantly elevated in the serum of men with PCa. It is now evident that p2PSA, %p2PSA, and PHI measurements improve the specificity of the available tests (PSA and derivatives) in detecting PCa. Moreover, increasing PHI values seem to correlate with more aggressive disease. Some studies have compared p2PSA and its derivatives with other new biomarkers and found p2PSA to be significantly more accurate. Indeed, the implementation of these tests in clinical practice has the potential to significantly increase the physician's ability to detect PCa and avoid unnecessary biopsies, while also having an effective impact on costs. Further studies in large, multicenter, prospective trials are required to confirm these encouraging results on the clinical utility of these new biomarkers.

The Prostate Health Index: a new test for the detection of prostate cancer

A major focus in urologic research is the identification of new biomarkers with improved specificity for clinically-significant prostate cancer. A promising new test based on prostate-specific antigen (PSA) is called the Prostate Health Index (PHI), which has recently been approved in the United States, Europe and Australia. PHI is a mathematical formula that combines total PSA, free PSA and [-2] proPSA. Numerous international studies have consistently shown that PHI outperforms its individual components for the prediction of overall and high-grade prostate cancer on biopsy. PHI also predicts the likelihood of progression during active surveillance, providing another noninvasive modality to potentially select and monitor this patient population. This article reviews the evidence on this new blood test with significant promise for both prostate cancer screening and treatment decision-making.

Preoperative prostate-specific antigen isoform p2PSA ≤ 22.5 pg/ml predicts advanced prostate cancer in patients undergoing radical prostatectomy

BACKGROUND

The prediction value of prostate-specific antigen (PSA) isoform [-2]proPSA (p2PSA) for detecting advanced prostate cancer (PCa) remains unclear. Our objective was to evaluate the additional clinical utility of p2PSA compared with total PSA (tPSA), free PSA (fPSA), and preoperative Gleason score (Gls) in predicting locally advanced PCa (pT3/T4) with high-accuracy discrimination. The aim was to develop a novel classification based on p2PSA and preoperative Gls for predicting advanced PCa.

MATERIALS AND METHODS

In 208 consecutive men diagnosed with clinically localized PCa who underwent radical prostatectomy, we determined the predictive and discriminatory accuracy of serum tPSA, fPSA, percentage of fPSA to tPSA, p2PSA, p2PSA density, percentage of p2PSA to fPSA, and the Prostate Health Index. The cutoff level of p2PSA with best accuracy was estimated. The novel classification was developed by analyzing the interaction between p2PSA and Gls in predicting pathologic outcomes using a chi-square automatic interaction detection analysis. Decision curve analysis was applied to test the clinical consequences of using the novel classification.

RESULTS

On univariate analyses, p2PSA, p2PSA density, percentage of p2PSA to fPSA, and Prostate Health Index were accurate but were not independent predictors by multivariate analysis. The p2PSA cutoff level of 22.5 pg/ml showed the best accuracy level for predicting and discriminating advanced diseases (area under the curve [AUC] = 0.725, sensitivity = 51.4%, specificity = 81.8%). By chi-square automatic interaction detection, univariate and multivariate analysis, a p2PSA level > 22.5 pg/ml was significantly associated with an increased frequency and risk of advanced disease. In patients with a p2PSA level ≤ 22.5 pg/ml, 91.8% of Gleason sum 6 PCa was organ confined. The combination of p2PSA and Gls enhanced slightly but significantly the predictive and discriminatory accuracy for advanced disease (0.6%-3.6%).

CONCLUSIONS

The p2PSA cutoff level of 22.5 pg/ml can accurately discriminate between organ-confined and advanced PCa. The additional use of p2PSA enhanced slightly the predictive accuracy for advanced PCa (pT3/pT4) and has limited additional predictive value in identifying aggressive PCa (Gls > 7a).

The impact of baseline [-2]proPSA-related indices on the prediction of pathological reclassification at 1 year during active surveillance for low-risk prostate cancer: the Japanese multicenter study cohort

Purpose

Active surveillance (AS) is one potential solution to avoiding the overtreatment of favorable prostate cancer. By handling the AS strategy more safely, tumor aggressiveness may be evaluated more accurately. The aim of the present study was to evaluate the predictive impact of baseline prostate-specific antigen (PSA) isoform [−2]proPSA (p2PSA)-related indices on the pathological reclassification at 1 year during an AS program.

Methods

Between 2002 and 2003, 134 males diagnosed with low-risk prostate cancer were registered in the Japanese multicenter study cohort as candidates for AS, and 118 (88 %) males actually proceeded to AS. Of the 118 patients, the 67 that underwent protocol biopsy at 1 year after beginning AS were enrolled in the present study. The predictive significance of various baseline clinicopathological features and p2PSA-related indices on pathological reclassification at 1 year after beginning AS were investigated.

Results

The pathological reclassification rate was 37.3 %. According to the univariate analysis, prostate volume (p = 0.049), number of biopsy cores (p = 0.047), percentage of positive biopsy cores (p = 0.023), p2PSA to free PSA ratio (%p2PSA) (p = 0.003) and prostate health index (phi) (p = 0.010) at baseline were significantly different between the reclassification and non-reclassification groups. By multivariate logistic regression analysis, baseline %p2PSA (p = 0.008) and phi (p = 0.008) were the only independent predictive factors for pathological upgrade at 1 year after AS commencement.

Conclusions

Baseline %p2PSA and phi may predict the pathological reclassification at 1 year after starting AS, which could be due to the under detection of clinically significant prostate cancer at AS enrollment.

Prostate Health Index (Phi) and Prostate Cancer Antigen 3 (PCA3) significantly improve prostate cancer detection at initial biopsy in a total PSA range of 2-10 ng/ml

Many efforts to reduce prostate specific antigen (PSA) overdiagnosis and overtreatment have been made. To this aim, Prostate Health Index (Phi) and Prostate Cancer Antigen 3 (PCA3) have been proposed as new more specific biomarkers. We evaluated the ability of phi and PCA3 to identify prostate cancer (PCa) at initial prostate biopsy in men with total PSA range of 2–10 ng/ml. The performance of phi and PCA3 were evaluated in 300 patients undergoing first prostate biopsy. ROC curve analyses tested the accuracy (AUC) of phi and PCA3 in predicting PCa. Decision curve analyses (DCA) were used to compare the clinical benefit of the two biomarkers. We found that the AUC value of phi (0.77) was comparable to those of %p2PSA (0.76) and PCA3 (0.73) with no significant differences in pairwise comparison (%p2PSA vs phi p = 0.673, %p2PSA vs. PCA3 p = 0.417 and phi vs. PCA3 p = 0.247). These three biomarkers significantly outperformed fPSA (AUC = 0.60), % fPSA (AUC = 0.62) and p2PSA (AUC = 0.63). At DCA, phi and PCA3 exhibited a very close net benefit profile until the threshold probability of 25%, then phi index showed higher net benefit than PCA3. Multivariable analysis showed that the addition of phi and PCA3 to the base multivariable model (age, PSA, %fPSA, DRE, prostate volume) increased predictive accuracy, whereas no model improved single biomarker performance. Finally we showed that subjects with active surveillance (AS) compatible cancer had significantly lower phi and PCA3 values (p<0.001 and p = 0.01, respectively). In conclusion, both phi and PCA3 comparably increase the accuracy in predicting the presence of PCa in total PSA range 2–10 ng/ml at initial biopsy, outperforming currently used %fPSA.

Sarcosine as a potential prostate cancer biomarker--a review

Prostate cancer (CaP) is the most common type of tumour disease in men. Early diagnosis of cancer of the prostate is very important, because the sooner the cancer is detected, the better it is treated. According to that fact, there is great interest in the finding of new markers including amino acids, proteins or nucleic acids. Prostate specific antigen (PSA) is commonly used and is the most important biomarker of CaP. This marker can only be detected in blood and its sensitivity is approximately 80%. Moreover, early stages cannot be diagnosed using this protein. Currently, there does not exist a test for diagnosis of early stages of prostate cancer. This fact motivates us to find markers sensitive to the early stages of CaP, which are easily detected in body fluids including urine. A potential is therefore attributed to the non-protein amino acid sarcosine, which is generated by glycine-N-methyltransferase in its biochemical cycle. In this review, we summarize analytical methods for quantification of sarcosine as a CaP marker. Moreover, pathways of the connection of synthesis of sarcosine and CaP development are discussed.

Multicenter evaluation of [-2]proprostate-specific antigen and the prostate health index for detecting prostate cancer

BACKGROUND

Total prostate-specific antigen (tPSA) is flawed for prostate cancer (PCa) detection. [-2]proprostate-specific antigen (p2PSA), a molecular isoform of free PSA (fPSA), shows higher specificity compared with tPSA or percentage of free PSA (%fPSA). The prostate health index (Phi), a measure based on p2PSA and calculated as p2PSA/fPSA × √tPSA, was evaluated in a multicenter study for detecting PCa.

METHODS

A total of 1362 patients from 4 different study sites who had tPSA values of 1.6-8.0 μg/L (668 patients with PCa, 694 without PCa) underwent ≥10 core biopsies. Serum concentrations of tPSA, fPSA (both calibrated against a WHO reference material), and p2PSA were measured on Access2 or DxI800 analyzers (Beckman Coulter).

RESULTS

The percentage ratio of p2PSA to fPSA (%p2PSA) and Phi were significantly higher in all PCa subcohorts (positive initial or repeat biopsy result or negative digital rectal examination) (P < 0.0001) compared with patients without PCa. Phi had the largest area under the ROC curve (AUC) (AUC = 0.74) and provided significantly better clinical performance for predicting PCa compared with %p2PSA (AUC = 0.72, P = 0.018), p2PSA (AUC = 0.63, P < 0.0001), %fPSA (AUC = 0.61) or tPSA (AUC = 0.56). Significantly higher median values of Phi were observed for patients with a Gleason score ≥7 (Phi = 60) compared with a Gleason score <7 (Phi = 53; P = 0.0018). The proportion of aggressive PCa (Gleason score ≥7) increased with the Phi score.

CONCLUSIONS

The results of this multicenter study show that Phi, compared with tPSA or %fPSA, demonstrated superior clinical performance in detecting PCa at tPSA 1.6-8.0 μg/L (i.e., approximately 2-10 μg/L in traditional calibration) and is better able to detect aggressive PCa.