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

The Prostate Health Index adds predictive value to multi-parametric MRI in detecting significant prostate cancers in a repeat biopsy population

Both multi-parametric MRI (mpMRI) and the Prostate Health Index (PHI) have shown promise in predicting a positive biopsy in men with suspected prostate cancer. Here we investigated the value of combining both tests in men requiring a repeat biopsy. PHI scores were measured in men undergoing re-biopsy with an mpMRI image-guided transperineal approach (n = 279, 94 with negative mpMRIs). The PHI was assessed for ability to add value to mpMRI in predicting all or only significant cancers (Gleason ≥7). In this study adding PHI to mpMRI improved overall and significant cancer prediction (AUC 0.71 and 0.75) compared to mpMRI + PSA alone (AUC 0.64 and 0.69 respectively). At a threshold of ≥35, PHI + mpMRI demonstrated a NPV of 0.97 for excluding significant tumours. In mpMRI negative men, the PHI again improved prediction of significant cancers; AUC 0.76 vs 0.63 (mpMRI + PSA). Using a PHI≥35, only 1/21 significant cancers was missed and 31/73 (42%) men potentially spared a re-biopsy (NPV of 0.97, sensitivity 0.95). Decision curve analysis demonstrated clinically relevant utility of the PHI across threshold probabilities of 5-30%. In summary, the PHI adds predictive performance to image-guided detection of clinically significant cancers and has particular value in determining re-biopsy need in men with a negative mpMRI.

Improving prediction models with new markers: a comparison of updating strategies

Background

New markers hold the promise of improving risk prediction for individual patients. We aimed to compare the performance of different strategies to extend a previously developed prediction model with a new marker.

Methods

Our motivating example was the extension of a risk calculator for prostate cancer with a new marker that was available in a relatively small dataset. Performance of the strategies was also investigated in simulations. Development, marker and test sets with different sample sizes originating from the same underlying population were generated. A prediction model was fitted using logistic regression in the development set, extended using the marker set and validated in the test set. Extension strategies considered were re-estimating individual regression coefficients, updating of predictions using conditional likelihood ratios (LR) and imputation of marker values in the development set and subsequently fitting a model in the combined development and marker sets. Sample sizes considered for the development and marker set were 500 and 100, 500 and 500, and 100 and 500 patients. Discriminative ability of the extended models was quantified using the concordance statistic (c-statistic) and calibration was quantified using the calibration slope.

Results

All strategies led to extended models with increased discrimination (c-statistic increase from 0.75 to 0.80 in test sets). Strategies estimating a large number of parameters (re-estimation of all coefficients and updating using conditional LR) led to overfitting (calibration slope below 1). Parsimonious methods, limiting the number of coefficients to be re-estimated, or applying shrinkage after model revision, limited the amount of overfitting. Combining the development and marker set using imputation of missing marker values approach led to consistently good performing models in all scenarios. Similar results were observed in the motivating example.

Conclusion

When the sample with the new marker information is small, parsimonious methods are required to prevent overfitting of a new prediction model. Combining all data with imputation of missing marker values is an attractive option, even if a relatively large marker data set is available.

Electronic supplementary material

The online version of this article (doi:10.1186/s12874-016-0231-2) contains supplementary material, which is available to authorized users.

Early Prediction of Therapy Response to Abiraterone Acetate Using PSA Subforms in Patients with Castration Resistant Prostate Cancer

The purpose of this study was to evaluate the prognostic ability of early changes of total prostate specific antigen (tPSA), free PSA (fPSA), [−2]proPSA and the Prostate Health Index (PHI) following initiation of Abiraterone-therapy in men with castration resistant prostate cancer (mCRPC). In 25 patients, PSA-subforms were analyzed before and at 8–12 weeks under therapy as prognosticators of progression-free-survival (PFS) and overall survival (OS). Comparing patients with a PFS < vs. ≥12 months by using Mann–Whitney–Wilcoxon Tests, the relative-median-change of tPSA (−0.1% vs. −86.8%; p = 0.02), fPSA (12.1% vs. −55.3%; p = 0.03) and [−2]proPSA (8.1% vs. −59.3%; p = 0.05) differed significantly. For men with ≤ vs. >15 months of OS there was a non-significant trend for a difference in the relative-median-change of fPSA (17.0% vs. −46.3%; p = 0.06). In Kaplan–Meier analyses, declining fPSA and [−2]proPSA were associated with a longer median PFS (13 months, 95% confidence interval (CI): 9.6–16.4 vs. 10 months, 95% CI: 3.5–16.5; p = 0.11), respectively. Correspondingly, decreasing fPSA and [−2]proPSA values indicated an OS of 32 months (95% CI: not reached (NR)) compared to 21 months in men with rising values (95% CI: 7.7–34.3; p = 0.14), respectively. We concluded that the addition of fPSA- and [−2]proPSA-changes to tPSA-information might be further studied as potential markers of early Abiraterone response in mCRPC patients.

Urinary Polyamines: A Pilot Study on Their Roles as Prostate Cancer Detection Biomarkers

Current screening methods towards prostate cancer (PCa) are not without limitations. Research work has been on-going to assess if there are other better tests suitable for primary or secondary screening of PCa to supplement the serum prostate specific antigen (PSA) test, which fails to work accurately in a grey zone of 4-10ng/ml. In this pilot study, the potential roles of urinary polyamines as prostate cancer biomarkers were evaluated. PCa, benign prostatic hyperplasia (BPH) patients and healthy controls (HC) showing PSA>4.0ng/ml were enrolled in the study. Their urine samples were obtained, and the urinary levels of putrescine (Put), spermidine (Spd) and spermine (Spm) were determined by ultra-high performance liquid chromatography coupled with triple quadrupole mass spectrometer (UPLC-MS/MS). Receiver operating characteristics (ROC) curve and Student’s t-test were used to evaluate their diagnostic accuracies. Among the three biogenic polyamines, Spm had demonstrated a good diagnostic performance when comparing their levels in PCa patients with BPH patients (1.47 in PCa vs 5.87 in BPH; p<0.0001). Results are in accordance with transrectal ultrasound prostatic biopsy (TRUSPB) results, with an area under curve (AUC) value of 0.83±0.03. Therefore urinary Spm shows potential to serve as a novel PCa diagnostic biomarker, which in turn can help to address the limited sensitivity and specificity problem of serum PSA test.

Beyond prostate-specific antigen: utilizing novel strategies to screen men for prostate cancer

PURPOSE OF REVIEW

The purpose of this article is to review blood and urine tests that are currently available and under investigation for a role in prostate cancer screening and detection.

RECENT FINDINGS

Compared with total prostate-specific antigen (PSA) alone, its combination with percentage free-to-total PSA contributes greater specificity for prostate cancer, and is a component of two newer blood tests called the 4kScore and Prostate Health Index. All three tests improve the prediction of high-grade disease and are commercially available options to aid in initial or repeat prostate biopsy decisions. PCA3 is a urinary marker that is currently available for repeat prostate biopsy decisions. Although PCA3 alone has inferior prediction of clinically significant disease and requires collection of urine after digital rectal examination, it may be combined with other clinical variables or other urine markers like TMPRSS2:ERG to improve performance. Little data are available to support a role for single nucleotide polymorphisms or other investigational markers in early detection.

SUMMARY

Several commercially available blood and urine tests have been shown to improve specificity of PSA for high-grade prostate cancer. Use of such tests would decrease unnecessary biopsy and overdiagnosis of indolent disease. Biopsy of men with moderately elevated PSA without use of such a reflex test should be discouraged.

Extended use of Prostate Health Index and percentage of [-2]pro-prostate-specific antigen in Chinese men with prostate specific antigen 10-20 ng/mL and normal digital rectal examination

PURPOSE

We investigated the extended use of Prostate Health Index (PHI) and percentage of [-2]pro-prostate-specific antigen (%p2PSA) in Chinese men with prostate-specific antigen (PSA) 10-20 ng/mL and normal digital rectal examination (DRE).

MATERIALS AND METHODS

All consecutive Chinese men with PSA 10-20 ng/mL and normal DRE who agreed for transrectal ultrasound (TRUS)-guided 10-core prostate biopsy were recruited. Blood samples were taken immediately before TRUS-guided prostate biopsy. The performances of total PSA (tPSA), %free-to-total PSA (%fPSA), %p2PSA, and PHI were compared using logistic regression, receiver operating characteristic, and decision curve analyses (DCA).

RESULTS

From 2008 to 2015, 312 consecutive Chinese men were included. Among them, 53 out of 312 (17.0%) men were diagnosed to have prostate cancer on biopsy. The proportions of men with positive biopsies were 6.7% in PHI<35, 22.8% in PHI 35-55, and 54.5% in PHI>55 (chi-square test, p<0.001). The area under curves (AUC) of the base model including age, tPSA and status of initial/repeated biopsy was 0.64. Adding %p2PSA and PHI to the base model improved the AUC to 0.79 (p<0.001) and 0.78 (p<0.001), respectively, and provided net clinical benefit in DCA. The positive biopsy rates of Gleason 7 or above prostate cancers were 2.2% for PHI<35, 7.9% for PHI 35-55, and 36.4% for PHI>55 (chi-square test, p<0.001). By utilizing the PHI cutoff of 35 to men with PSA 10-20 ng/mL and normal DRE, 57.1% (178 of 312) biopsies could be avoided.

CONCLUSIONS

Both PHI and %p2PSA performed well in predicting prostate cancer and high grade prostate cancer. The use of PHI and %p2PSA should be extended to Chinese men with PSA 10-20 ng/mL and normal DRE.

Prostate cancer biomarkers: Are we hitting the mark?

Purpose

Localised prostate cancer diagnosis and management is increasingly complex due to its heterogeneous progression and prognostic subgroups. Pitfalls in current screening and diagnosis have prompted the search for accurate and invasive molecular and genetic biomarkers for prostate cancer. Such tools may be able to distinguish clinically significant cancers from less aggressive variants to assist with prostate cancer risk stratification and guide decisions and healthcare algorithms. We aimed to provide a comprehensive review of the current prostate cancer biomarkers available and in development.

Methods

MEDLINE and EMBASE databases searches were conducted to identify articles pertaining to the use of novel biomarkers for prostate cancer.

Results

A growing number of novel biomarkers are currently under investigation. Such markers include urinary biomarkers, serology-based markers or pathological tissue assessments of molecular and genetic markers. While limited clinical data is present for analysis, early results appear promising. Specifically, a combination of serum and urinary biomarkers (Serum PSA + Urinary PCA3 + Urinary TMPRSS2-ERG fusion) appears to provide superior sensitivity and specificity profiles compared to traditional diagnostic approaches (AUC 0.88).

Conclusion

The accurate diagnosis and risk stratification of prostate cancer is critical to ensure appropriate intervention. The development of non-invasive biomarkers can add to the information provided by current screening practices and allows for individualised risk stratification of patients. The use of these biomarkers appears to increase the sensitivity and specificity of diagnosis of prostate cancer. Further studies are necessary to define the appropriate use and time points of each biomarker and their effect on the management algorithm of prostate cancer.

Prostate health index (PHI) and prostate-specific antigen (PSA) predictive models for prostate cancer in the Chinese population and the role of digital rectal examination-estimated prostate volume

PURPOSE

To investigate PSA- and PHI (prostate health index)-based models for prediction of prostate cancer (PCa) and the feasibility of using DRE-estimated prostate volume (DRE-PV) in the models.

METHODS

This study included 569 Chinese men with PSA 4-10 ng/mL and non-suspicious DRE with transrectal ultrasound (TRUS) 10-core prostate biopsies performed between April 2008 and July 2015. DRE-PV was estimated using 3 pre-defined classes: 25, 40, or 60 ml. The performance of PSA-based and PHI-based predictive models including age, DRE-PV, and TRUS prostate volume (TRUS-PV) was analyzed using logistic regression and area under the receiver operating curves (AUC), in both the whole cohort and the screening age group of 55-75.

RESULTS

PCa and high-grade PCa (HGPCa) was diagnosed in 10.9 % (62/569) and 2.8 % (16/569) men, respectively. The performance of DRE-PV-based models was similar to TRUS-PV-based models. In the age group 55-75, the AUCs for PCa of PSA alone, PSA with DRE-PV and age, PHI alone, PHI with DRE-PV and age, and PHI with TRUS-PV and age were 0.54, 0.71, 0.76, 0.78, and 0.78, respectively. The corresponding AUCs for HGPCa were higher (0.60, 0.70, 0.85, 0.83, and 0.83). At 10 and 20 % risk threshold for PCa, 38.4 and 55.4 % biopsies could be avoided in the PHI-based model, respectively.

CONCLUSIONS

PHI had better performance over PSA-based models and could reduce unnecessary biopsies. A DRE-assessed PV can replace TRUS-assessed PV in multivariate prediction models to facilitate clinical use.

Clinical Perspective of Prostate Cancer

Prostate cancer is the most common noncutaneous cancer affecting men today. It largely affects men in the fifth and sixth decade of life. Screening for prostate cancer, though controversial, is still the only way to detect early prostate cancer. Multiple newer options such as blood tests and genetic markers are being used in the clinical domain today to improve cancer detection and avoid unnecessary biopsies. To date, biopsy of the prostate remains the only modality to stratify the grade of cancer. Significant improvements in the imaging technology have improved localizing and detecting the disease. Treatment of prostate cancer is stratified on the basis of the grade and volume of the disease. There are multiple treatment options involved in the management of prostate cancer. Treatment of localized prostate cancer still continues to have very high cure rates and long-term cancer-specific survival rates.

Elevated Prostate Health Index (phi) and Biopsy Reclassification During Active Surveillance of Prostate Cancer

The Prostate Health Index (phi) has been FDA approved for decision-making regarding prostate biopsy. Phi has additionally been shown to positively correlate with tumor volume, extraprostatic disease and higher Gleason grade tumors. Here we describe a case in which an elevated phi encouraged biopsy of a gentleman undergoing active surveillance leading to reclassification of his disease as high risk prostate cancer.

Clinical performance of prostate health index in men with tPSA>10ng/ml: Results from a multicentric European study

BACKGROUND

Evidence regarding the diagnostic accuracy of a [-2]proPSA derivative, namely, the prostate health index (PHI), to predict the presence of prostate cancer (PCa) in individuals with high total prostate-specific antigen (tPSA) levels is lacking. We tested the hypothesis that these markers could assist clinicians in the biopsy decision path of patients with tPSA>10ng/ml.

METHODS

The primary endpoint was to evaluate the sensitivity, specificity, and diagnostic accuracy of PHI in determining the presence of PCa at biopsy in comparison to tPSA, free PSA, and % of free to total PSA. We calculated the number of prostate biopsies that could have been spared by using this marker to decide whether or not to perform a biopsy. A secondary endpoint was to determine the relationship between PHI and PCa characteristics.

RESULTS

The PCa was diagnosed in 136 of 262 patients (51.9%). Total PSA and PHI values were significantly higher (P<0.005) and % of free to total PSA values significantly lower (P<0.0001) in patients with PCa relative to those with a negative biopsy. In multivariable logistic regression models, PHI achieved the independent predictor status and significantly increased the accuracy of the base multivariable model by an extent of 8.2% (P = 0.0005). The inclusion of PHI in the biopsy decision path would decrease the number of unnecessary biopsies by an extent of 50.0%, while missing only few cases with clinically significant PCa. Finally, Gleason score was significantly related to PHI levels.

CONCLUSIONS

The results of our study support the diagnostic effectiveness of PHI even in patients with tPSA >10ng/ml. Further validation studies with larger sample size are needed to corroborate our findings.

NCCN Guidelines Insights: Prostate Cancer Early Detection, Version 2.2016

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Prostate Cancer Early Detection provide recommendations for prostate cancer screening in healthy men who have elected to participate in an early detection program. The NCCN Guidelines focus on minimizing unnecessary procedures and limiting the detection of indolent disease. These NCCN Guidelines Insights summarize the NCCN Prostate Cancer Early Detection Panel's most significant discussions for the 2016 guideline update, which included issues surrounding screening in high-risk populations (ie, African Americans, BRCA1/2 mutation carriers), approaches to refine patient selection for initial and repeat biopsies, and approaches to improve biopsy specificity.

A urologist's perspective on prostate cancer imaging: past, present, and future

Prostate cancer is unique in that unlike other solid organ malignancies, only recently has imaging been employed to routinely detect and localize disease. The introduction of transrectal ultrasound was a significant development, transitioning digitally guided prostate biopsies to ultrasound guidance. The arrival of multiparametric MRI has become the next major step, transforming the way Urologist's diagnose, stage, and treat prostate cancer. Recent recommendations against PSA screening have changed the landscape of urologic oncology with the changing needs being reflected in the initiation of additional robust imaging techniques at different time points in prostate cancer care. The current review aims to provide a clinical perspective in the history, current standard of care, and novel imaging modalities in the evaluation of prostate cancer.

Screening for Prostate Cancer-Beyond Total PSA, Utilization of Novel Biomarkers

Urology has been beset by several major trends that have shifted the entire paradigm for prostate cancer screening. These stem from a backlash against overdiagnosis and overtreatment due to prostate-specific antigen (PSA)-based screening efforts and have led national societies to modify their guidelines. More importantly, the public outcry has shifted the focus of early detection from an effort to diagnose any and all prostate cancers to an effort to diagnose clinically significant prostate cancers at an early stage. This review provides an update on contemporary biomarkers for prostate cancer that may be used to supplement PSA-based screening approaches.

[Primary candidate rna biomarker screening by RNA-seq for prostate cancer diagnostics]

The RNA-seq approach for prostate cancer candidate RNA biomarkers screening in plasma and urine obtained by minimally invasive or noninvasive methods is proved to be feasible. Significant amount of RNA biomarkers associated with prostate cancer according to the literature were found in plasma and urine samples obtained from patients with benign prostatic hyperplasia (BPH). The number of detected markers was shown to vary in accordance with method of library preparation used for transcriptome profiling. The detection of known RNA biomarkers for prostate cancer in urine and plasma samples shows the feasibility of such method for minimally invasive diagnostics. The fact of presence of the same RNA biomarkers in samples from patients with BPH suggests their possible lack of specificity and confirms the need for further research in this area.

[-2]proPSA versus ultrasensitive PSA fluctuations over time in the first year from radical prostatectomy, in an high-risk prostate cancer population: A first report

Background

[−2]proPSA and its derivatives have an higher diagnostic accuracy than PSA in predicting prostate cancer (PCa). In alternative to PSA, ultrasensitive PSA (uPSA) and [−2]proPSA could be potentially useful in recurrent disease detection. This research focused on [−2]proPSA and uPSA fluctuations over time and their possible clinical and pathological determinants, in the first year after RP.

Methods

A cohort of 106 consecutive patients, undergoing RP for high-risk prostate cancer (pT3/pT4 and/or positive margins), was enrolled. No patient received either preoperative/postoperative androgen deprivation therapy or immediate adjuvant RT, this latter for patient choice. [−2]proPSA and uPSA were measured at 1, 3, 6, 9, 12 months after RP; their trends over time were estimated by the mixed-effects linear model. The uPSA relapse was defined either as 3 rising uPSA values after nadir or 2 consecutive uPSA >0.2 ng/ml after RP.

Results

The biochemical recurrence (BCR) rate at 1 year after RP was either 38.6 % (in case of 3 rising uPSA values) or 34.9 % (in case of PSA >0.2 ng/ml after nadir), respectively. The main risk factors for uPSA fluctuations over time were PSA at diagnosis >8 ng/ml (p = 0.014), pT (p = 0.038) and pN staging (p = 0.001). In turn, PSA at diagnosis >8 ng/ml (p = 0.012) and pN (p < 0.001) were the main determinants for [−2]proPSA trend over time. In a 39 patients subgroup, uPSA decreased from month 1 to 3, while [−2]proPSA increased in 90 % of them; subsequently, both uPSA and [−2]proPSA increased in almost all cases. The [−2]proPSA trend over time was independent from BCR status either in the whole cohort as well in the 39 men subgroup.

Conclusions

Both uPSA and [−2]proPSA had independent significant fluctuations over time. PSA at diagnosis >8 ng/ml and pathological staging significantly modified both these trends over time. Since BCR was not confirmed as determinant of [−2]proPSA fluctuations, its use as marker of early biochemical relapse may not be actually recommended, in an high-risk prostate cancer patients population.

Serum Vitamin D is Not Helpful for Predicting Prostate Cancer Aggressiveness Compared with the Prostate Health Index

PURPOSE

We evaluated the usefulness of serum 25-hydroxyvitamin D as a marker of aggressive prostate cancer and for active surveillance compared to PHI (Prostate Health Index).

MATERIALS AND METHODS

Of 480 prospectively biopsied men 222 had prostate cancer and 258 had no evidence of malignancy. In all men prostate specific antigen was less than 20 ng/ml. We measured 25-hydroxyvitamin D, prostate specific antigen, free prostate specific antigen and -2proPSA using a commercially available immunoassay system. PHI was calculated according to the equation, -2proPSA/free prostate specific antigen × √PSA. We determined 25-hydroxyvitamin D using a 2-step competitive binding immunoenzymatic vitamin D assay.

RESULTS

The 25-hydroxyvitamin D concentrations were not associated with Gleason grade according to the 2014 ISUP (International Society of Urological Pathology) consensus conference Gleason grading system. PHI values were higher with increasing Gleason grade. Median 25-hydroxyvitamin D did not differ between men with prostate cancer vs no evidence of malignancy (50.6 vs 48.2 nmol/l, p = 0.192) or in ISUP Gleason subgroups despite seasonal variations of 25-hydroxyvitamin D. However, PHI values significantly differed between the subgroup with no evidence of malignancy and all Gleason subgroups (p <0.0001). The ROCs of all men revealed an advantage of PHI over 25-hydroxyvitamin D (AUC 0.78 vs 0.535, p <0.0001). PHI could also significantly better separate patients with no evidence of malignancy from those with nonaggressive disease (ISUP Gleason grade 1) from those with aggressive prostate cancer (ISUP Gleason grades 2-5).

CONCLUSIONS

It remains highly improbable that 25-hydroxyvitamin D could be used as decision or selection marker for aggressive prostate cancer or for active surveillance compared to accepted markers, as recently suggested.

Prostate Health Index and %p2PSA Predict Aggressive Prostate Cancer Pathology in Chinese Patients Undergoing Radical Prostatectomy

PURPOSE

To investigate the performance of prostate health index (PHI) and percentage prostate-specific antigen (PSA) isoform [-2]proPSA (%p2PSA) in predicting pathologic outcomes at radical prostatectomy (RP) in a Chinese population.

METHODS

We performed a prospective study of 135 prostate cancer patients with RP. The accuracy of preoperative %p2PSA (= p2PSA/free PSA) and PHI [= (p2PSA/free PSA) × √PSA] in predicting pathologic outcomes of RP including pT3 disease, pathologic Gleason score (pGS) ≥7, Gleason score (GS) upgrade at RP, tumor volume >0.5 ml, and Epstein criteria for significant tumor were calculated using multivariate analyses and area under the curve. The base model in multivariate analysis included age, PSA, abnormal digital rectal examination, and biopsy GS.

RESULTS

PHI was significantly higher in patients with pT3 or pGS ≥ 7 (p < 0.001), pT3 disease (p = 0.001), pGS ≥ 7 (p < 0.001), GS upgrade (p < 0.001), tumor volume >0.5 ml (p < 0.001), and Epstein criteria for significant tumor (p = 0.001). %p2PSA was also significantly higher in all the above outcomes. The risk of pT3 or pGS ≥ 7 was 16.1 % for PHI < 35 and 60.8 % for PHI > 35 (sensitivity 84.2 %, specificity of 60.3 %), and the risk of tumor volume >0.5 ml was 25.5 % for PHI < 35 and 72.6 % for PHI > 35 (sensitivity 79.1 %, specificity 67.2 %). In multivariate analysis, adding %p2PSA or PHI to the base model significantly improved the accuracy (area under the curve) in predicting pT3 or pGS ≥ 7 (by 7.2-7.9 %), tumor volume >0.5 ml (by 10.3-12.8 %), and Epstein criteria for significant tumor (by 13.9-15.9 %). Net clinical benefit was observed in decision curve analyses for prediction of both tumor volume >0.5 ml, and pT3 or pGS ≥ 7.

CONCLUSIONS

Both PHI and %p2PSA predict aggressive and significant pathologies in RP in Chinese men. This enabled identification of nonaggressive cancers for better counseling on active surveillance or treatment.

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.

The Cost-Effectiveness of Prostate Cancer Detection with the Use of Prostate Health Index

BACKGROUND

Clinical trial results suggested that prostate-specific antigen (PSA) screening can reduce prostate cancer mortality. Nevertheless, because the specificity of the PSA test for cancer detection is low, it leads to many negative biopsies. The Beckman Coulter Prostate Health Index (PHI) testing demonstrates improved specificity compared with the PSA-only screening and therefore may improve the cost-effectiveness of prostate cancer detection.

OBJECTIVE

To examine the cost-effectiveness of adding PHI testing to improve cancer detection for men with elevated serum PSA.

METHODS

A microsimulation model, based on the results of the European Randomized Study of Screening for Prostate Cancer trial, was used to evaluate the effects of PSA screening and PHI reflex testing. We predicted the numbers of prostate cancers, negative biopsies, deaths, quality-adjusted life-years gained, and cost-effectiveness of both PSA (cutoff 3 ng/mL) and PHI (cutoff 25) testing methods for a European population, screened from age 50 to 75 years at 4-year intervals.

RESULTS

When the PHI test was added to the PSA screening, for men with a PSA between 3 and 10 ng/mL, the model predicted a 23% reduction in negative biopsies. This would lead to a 17% reduction in costs for diagnostics and 1% reduction in total costs for prostate cancer. The cost-effectiveness (3.5% discounted) was 11% better. Limitations found were the modeling assumptions on the sensitivity and specificity of PHI by tumor stage and cutoff values.

CONCLUSIONS

Compared with PSA-only screening, the use of a PHI test can substantially reduce the number of negative biopsies and improve the cost-effectiveness of prostate cancer detection.

Molecular Form Differences Between Prostate-Specific Antigen (PSA) Standards Create Quantitative Discordances in PSA ELISA Measurements

The prostate-specific antigen (PSA) assays currently employed for the detection of prostate cancer (PCa) lack the specificity needed to differentiate PCa from benign prostatic hyperplasia and have high false positive rates. The PSA calibrants used to create calibration curves in these assays are typically purified from seminal plasma and contain many molecular forms (intact PSA and cleaved subforms). The purpose of this study was to determine if the composition of the PSA molecular forms found in these PSA standards contribute to the lack of PSA test reliability. To this end, seminal plasma purified PSA standards from different commercial sources were investigated by western blot (WB) and in multiple research grade PSA ELISAs. The WB results revealed that all of the PSA standards contained different mass concentrations of intact and cleaved molecular forms. Increased mass concentrations of intact PSA yielded higher immunoassay absorbance values, even between lots from the same manufacturer. Standardization of seminal plasma derived PSA calibrant molecular form mass concentrations and purification methods will assist in closing the gaps in PCa testing measurements that require the use of PSA values, such as the % free PSA and Prostate Health Index by increasing the accuracy of the calibration curves.

Prostate-specific antigen-based population screening for prostate cancer: current status in Japan and future perspective in Asia

In Western countries, clinical trials on prostate cancer screening demonstrated a limited benefit for patient survival. In the Asia-Pacific region, including Japan, the rate of prostate-specific antigen (PSA) testing remains very low compared with Western countries, and the benefits of population-based screening remain unclear. This review describes the current status of population screening and diagnosis for prostate cancer in Japan and discusses the efficacy of population screening for the Asian population. Since the 1990s, screening systems have been administered by each municipal government in Japan, and decreases in the prostate cancer mortality rate are expected in some regions where the exposure rate to PSA screening has increased markedly. A population-based screening cohort revealed that the proportion of metastatic disease in cancer detected by screening gradually decreased according to the increased exposure rate, and a decreasing trend in the proportion of cancer with high serum PSA levels after population screening was started. The prognosis of the prostate cancer detected by population screening was demonstrated to be more favorable than those diagnosed outside of the population screening. Recent results in screening cohorts demonstrated the efficacy of PSA. These recent evidences regarding population-based screening in Japan may contribute to establishing the optimal prostate cancer screening system in Asian individuals.

Immunochemical Assays and Nucleic-Acid Detection Techniques for Clinical Diagnosis of Prostate Cancer

Prostate cancer (PCa) is a significant cause of morbidity and mortality and the most common cancer in men in Europe, North America, and some parts of Africa. The established methods for detecting PCa are normally based on tests using Prostate Specific Antigen (PSA) in blood, Prostate cancer antigen 3 (PCA3) in urine and tissue Alpha-methylacyl-CoA racemase (AMACR) as tumour markers in patient samples. Prior to the introduction of PSA in clinics, prostatic acid phosphatase (PAP) was the most widely used biomarker. An early diagnosis of PCa through the detection of these biomarkers requires the availability of simple, reliable, cost-effective and robust techniques. Immunoassays and nucleic acid detection techniques have experienced unprecedented growth in recent years and seem to be the most promising analytical tools. This growth has been driven in part by the surge in demand for near-patient-testing systems in clinical diagnosis. This article reviews immunochemical assays, and nucleic-acid detection techniques that have been used to clinically diagnose PCa.

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.

Clinical utility of the (-2)proPSA and evaluation of the evidence: a systematic review

Diagnostic studies usually provide important information about the analytical and diagnostic performances. We investigated the clinical utility of (-2)proPSA in identifying patients with prostate cancer (PCa).

We performed electronic searches in five databases as well as a list of reference literature. Studies were included if they evaluated the diagnostic accuracy of (-2)proPSA in men with PSA value ranged from 2.0 to 10 μg/L. We also analyzed data about total PSA (tPSA), %(-2)proPSa, freePSA (fPSA), its percentage (%fPSA) and the prostate health index (phi). The selection of the studies, the screening of the full texts and the data extraction, as well as the assessment of risk of bias using the QUADAS-2 tool were conducted independently by two authors. Grading the quality of the evidence was carried out according to the GRADE method. The random effects model was used for the meta-analyses.

We included 17 studies, including 6912 patients. The pooled sensitivity of (-2)proPSA was 90% and the summary specificity was 13%. The tPSA sensitivity and specificity were 89% and 25%, respectively. Considering (-2)proPSA, 225 men out of 1000 have been identified having PCa true positives (TP). However, 652 persons have been incorrectly identified and undergo biopsy. The majority of studies were judged to carry a moderate risk of bias. Therefore, the overall quality of evidences was deemed to be low.

The (-2)proPSA could be useful to identify men at risk of PCa, but its accuracy still remains uncertain and the level of evidence does not support an improved clinical utility.

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.

Urinary Volatile Organic Compounds for the Detection of Prostate Cancer

The aim of this work was to investigate volatile organic compounds (VOCs) emanating from urine samples to determine whether they can be used to classify samples into those from prostate cancer and non-cancer groups. Participants were men referred for a trans-rectal ultrasound-guided prostate biopsy because of an elevated prostate specific antigen (PSA) level or abnormal findings on digital rectal examination. Urine samples were collected from patients with prostate cancer (n = 59) and cancer-free controls (n = 43), on the day of their biopsy, prior to their procedure. VOCs from the headspace of basified urine samples were extracted using solid-phase micro-extraction and analysed by gas chromatography/mass spectrometry. Classifiers were developed using Random Forest (RF) and Linear Discriminant Analysis (LDA) classification techniques. PSA alone had an accuracy of 62–64% in these samples. A model based on 4 VOCs, 2,6-dimethyl-7-octen-2-ol, pentanal, 3-octanone, and 2-octanone, was marginally more accurate 63–65%. When combined, PSA level and these four VOCs had mean accuracies of 74% and 65%, using RF and LDA, respectively. With repeated double cross-validation, the mean accuracies fell to 71% and 65%, using RF and LDA, respectively. Results from VOC profiling of urine headspace are encouraging and suggest that there are other metabolomic avenues worth exploring which could help improve the stratification of men at risk of prostate cancer. This study also adds to our knowledge on the profile of compounds found in basified urine, from controls and cancer patients, which is useful information for future studies comparing the urine from patients with other disease states.

RNA biomarkers to facilitate the identification of aggressive prostate cancer

A large number of men are diagnosed with prostate cancer each year, but many will not experience morbidity or mortality as a result of their cancers. Therefore, biomarkers for prostate cancer are necessary to carefully select patients for initial diagnostic biopsy or to facilitate care decisions for men who have already been diagnosed with prostate cancer. RNA-based approaches to biomarker discovery allow the investigation of non-coding RNAs, gene fusion transcripts, splice variants, and multi-gene expression panels in tissue, urine, or blood as opportunities to improve care decisions. This review focuses on RNA biomarkers that are available as commercial assays, and therefore already available for potential clinical use, as well as providing an overview of newer RNA biomarkers that are in earlier stages of clinical development.

Current biomarkers for diagnosing of prostate cancer

Prostate cancer (PCa) is mostly detected by prostate-specific antigen (PSA) as one of the most widely used tumor markers. But PSA is limited with its low specificity. The prostate health index (phi) can improve specificity over percent free and total PSA and correlates with aggressive cancer. The urinary PCA3 also shows its utility to detect PCa but its correlation with aggressiveness and the low sensitivity at high values are limitations. While the detection of alterations of the androgen-regulated TMPRSS2 and ETS transcription factor genes in tissue of ˜50% of all PCa patients was one research milestone, the urinary assay should only be used in combination with PCA3. Both US FDA-approved markers phi and PCA3 perform equally.

PSA, PSA derivatives, proPSA and prostate health index in the diagnosis of prostate cancer

Currently, prostate- specific antigen (PSA) is the most common oncological marker used for prostate cancer screening. However, high levels of PSA in benign prostatic hyperplasia and prostatitis decrease the specificity of PSA as a cancer marker. To increase the specificity of PSA, PSA derivatives and PSA kinetics have been used. However, these new techniques were not able to increase the diagnostic specificity for prostate cancer. Therefore, the search for new molecules and derivatives of PSA continues. With the aim of increasing the specificity of prostate cancer diagnosis, proPSA and the Prostate Health Index have been introduced. In this review, the roles of PSA, PSA derivatives, proPSA and the Prostate Health Index in Prostate Cancer diagnosis are examined.

Approaches for Initial Prostate Biopsy and Antibiotic Prophylaxis

CONTEXT

Debate on the optimal technique to use as an initial prostate biopsy (PB) strategy is continually evolving.

OBJECTIVE

To review recent advances and current recommendations regarding initial PB and antibiotic prophylaxis.

EVIDENCE ACQUISITION

A nonsystematic review of the literature was performed up to October 2014 using the PubMed and Embase databases. Articles were selected with preference for the highest level of evidence in publications within the past 5 yr.

EVIDENCE SYNTHESIS

The decision to perform PB is still based on an abnormal digital rectal examination or increased prostate0specific antigen (PSA) level without clear consensus about the absolute cutoff. Several biomarkers have been suggested to improve PSA-based PB decision-making and minimize overdiagnosis and overtreatment. The random 12-core transrectal (TR) ultrasound-guided approach remains the standard-of-care technique for PB. A >12-core scheme may be considered as an alternative in a single patient given his clinical features (large volume, low PSA levels). Transperineal biopsies may only be considered as an alternative to the TR route in special situations. Nevertheless, given the increase in antimicrobial resistance, the impact on the post-biopsy sepsis rate should be assessed in well-designed clinical trials. Imaging-guided targeted PB strategies, combined or not with random PBs, may represent the future of prostate cancer diagnosis by reducing the number of PBs and improving decision-making.

CONCLUSIONS

The 12-core TR scheme remains the standard of care for initial PB. The actual trend for PB strategy, with the aim of avoiding overdiagnosis of very low-risk cancers, could rapidly change our current indications and techniques through new biomarkers and imaging-guided targeted strategies. Nevertheless, the cost-benefit balance of these techniques should be closely assessed in the setting of initial PB strategy.

PATIENT SUMMARY

This review highlights current recommendations for prostate biopsy and possible advances in the near future.

Current early diagnostic biomarkers of prostate cancer

Prostate cancer (PCa) has become to have the highest incidence and the second mortality rate in western countries, affecting men's health to a large extent. Although prostate-specific antigen (PSA) was discovered to help diagnose the cancer in an early stage for decades, its specificity is relative low, resulting in unnecessary biopsy for healthy people and over-treatment for patients. Thus, it is imperative to identify more and more effective biomarkers for early diagnosis of PCa in order to distinguish patients from healthy populations, which helps guide an early treatment to lower disease-related mortality by noninvasive or minimal invasive approaches. This review generally describes the current early diagnostic biomarkers of PCa in addition to PSA and summarizes the advantages and disadvantages of these biomarkers.

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.

Diagnostic associations of gene expression signatures in prostate cancer tissue

PURPOSE OF REVIEW

Over the past several years, multiple biomarkers designed to improve prostate cancer risk stratification have become commercially available, while others are still being developed. In this review, we focus on the evidence supporting recently reported biomarkers, with a focus on gene expression signatures.

RECENT FINDINGS

Many recently developed biomarkers are able to improve upon traditional risk assessment at nearly all stages of disease. Prominent examples are reviewed in this article. ConfirmMDx uses gene methylation patterns to improve detection of clinically significant cancer following negative biopsy. Both the Prolaris and Oncotype DX Genomic Prostate Score tests can improve risk stratification following biopsy, especially among men who are eligible for active surveillance. Prolaris and the Decipher genomic classifier have been associated with risk of adverse outcome following prostatectomy, while Oncotype DX is being studied in this setting. Finally, recent reports of the association of androgen receptor-V7 in circulating tumor cells with resistance to enzalutamide and abiraterone raise the possibility of extending the use of genetic biomarkers to advanced disease.

SUMMARY

With the development of multiple genetic expression panels in prostate cancer, careful study and validation of these tests and integration into clinical practice will be critical to realizing the potential of these tools.

Addressing the need for repeat prostate biopsy: new technology and approaches

No guidelines currently exist that address the need for rebiopsy in patients with a negative diagnosis of prostate cancer on initial biopsy sample analysis. Accurate diagnosis of prostate cancer in these patients is often complicated by continued elevation of serum PSA levels that are suggestive of prostate cancer, resulting in a distinct management challenge. Following negative initial findings of biopsy sample analysis, total serum PSA levels and serum PSA kinetics are ineffective indicators of a need for a repeat biopsy; therefore, patients suspected of having prostate cancer might undergo several unnecessary biopsy procedures. Several alternative strategies exist for identifying men who might be at risk of prostate cancer despite negative findings of biopsy sample analysis. Use of other serum PSA-related measurements enables more sensitive and specific diagnosis and can be combined with knowledge of clinicopathological features to improve outcomes. Other options include the FDA-approved Progensa(®) test and prostate imaging using MRI. Newer tissue-based assays that measure methylation changes in normal prostate tissue are currently being developed. A cost-effective strategy is proposed in order to address this challenging clinical scenario, and potential directions of future studies in this area are also described.

Multicenter Evaluation of the Prostate Health Index to Detect Aggressive Prostate Cancer in Biopsy Naïve Men

PURPOSE

We evaluated the ability of PHI to discriminate aggressive prostate cancer from indolent or no cancer in a biopsy naïve population.

MATERIALS AND METHODS

Two independent prospective cohorts of 561 and 395 subjects, respectively, with no prior prostate biopsy who were enrolled at different clinical sites were used to validate the results. We compared the diagnostic specificity of PHI to prebiopsy total and percent free prostate specific antigen using prostate biopsy results. We also determined the optimal PHI threshold to discriminate aggressive prostate cancer (Gleason score 7 or greater) from indolent or no prostate cancer (Gleason score 6 or less).

RESULTS

In the primary cohort higher PHI values were significantly associated with Gleason score 7 or greater. The AUC to detect aggressive prostate cancer was 0.815. At 95% sensitivity PHI specificity was 36.0% vs 17.2% and 19.4% for total and percent free prostate specific antigen, respectively. At 95% sensitivity for detecting aggressive prostate cancer the optimal PHI cutoff was 24, which would help avoid 41% of unnecessary biopsies. A cutoff of 24 led to 36% biopsies avoided with few aggressive cancers missed. These results were confirmed in the validation cohort.

CONCLUSIONS

The PHI detected aggressive prostate cancer with better specificity than total and percent free prostate specific antigen in a biopsy naïve population. It could be a useful tool to decrease unnecessary prostate biopsies.

Comparison Between the Four-kallikrein Panel and Prostate Health Index for Predicting Prostate Cancer

BACKGROUND

The four-kallikrein panel and the Prostate Health Index (PHI) have been shown to improve prediction of prostate cancer (PCa) compared with prostate-specific antigen (PSA). No comparison of the four-kallikrein panel and PHI has been presented.

OBJECTIVE

To compare the four-kallikrein panel and PHI for predicting PCa in an independent cohort.

DESIGN, SETTING, AND PARTICIPANTS

Participants were from a population-based cohort of PSA-tested men in Stockholm County. We included 531 men with PSA levels between 3 and 15 ng/ml undergoing first-time prostate biopsy during 2010-2012.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Models were fitted to case status. We computed calibration curves, the area under the receiver-operating characteristics curve (AUC), decision curves, and percentage of saved biopsies.

RESULTS AND LIMITATIONS

The four-kallikrein panel showed AUCs of 69.0 when predicting any-grade PCa and 71.8 when predicting high-grade cancer (Gleason score ≥7). Similar values were found for PHI: 70.4 and 71.1, respectively. Both models had higher AUCs than a base model with PSA value and age (p<0.0001 for both); differences between models were not significant. Sensitivity analyses including men with any PSA level or a previous biopsy did not materially affect our findings. Using 10% predicted risk of high-grade PCa by the four-kallikrein panel or PHI of 39 as cut-off for biopsy saved 29% of performed biopsies at a cost of delayed diagnosis for 10% of the men with high-grade cancers. Both models showed limited net benefit in decision analysis. The main study limitation was lack of digital rectal examination data and biopsy decision being based on PSA information.

CONCLUSIONS

The four-kallikrein panel and PHI similarly improved discrimination when predicting PCa and high-grade PCa. Both are simple blood tests that can reduce the number of unnecessary biopsies compared with screening with total PSA, representing an important new option to reduce harm.

PATIENT SUMMARY

Prostate-specific antigen screening is controversial due to limitations of the test. We found that two blood tests, the Prostate Health Index and the four-kallikrein panel, performed similarly and could both aid in decision making among Swedish men undergoing a prostate biopsy.

Urinary biomarkers for the detection of prostate cancer in patients with high-grade prostatic intraepithelial neoplasia

INTRODUCTION

High-grade prostatic intraepithelial neoplasia (HGPIN) is a recognized precursor stage of PCa. Men who present HGPIN in a first prostate biopsy face years of active surveillance including repeat biopsies. This study aimed to identify non-invasive prognostic biomarkers that differentiate early on between indolent HGPIN cases and those that will transform into actual PCa.

METHODS

We measured the expression of 21 candidate mRNA biomarkers using quantitative PCR in urine sediment samples from a cohort of 90 patients with initial diagnosis of HGPIN and a posterior follow up of at least two years. Uni- and multivariate statistical analyses were applied to analyze the candidate biomarkers and multiplex models using combinations of these biomarkers.

RESULTS

PSMA, PCA3, PSGR, GOLM, KLK3, CDH1, and SPINK1 behaved as predictors for PCa presence in repeat biopsies. Multiplex models outperformed (AUC = 0.81-0.86) the predictive power of single genes, including the FDA-approved PCA3 (AUC = 0.70). With a fixed sensitivity of 95%, the specificity of our multiplex models was of 41-58%, compared to the 30% of PCA3. The PPV of our models (30-38%) was also higher than the PPV of PCA3 (27%), suggesting that benign cases could be more accurately identified. Applying statistical models, we estimated that 33% to 47% of repeat biopsies could be prevented with a multiplex PCR model, representing an easy applicable and significant advantage over the current gold standard in urine sediment.

DISCUSSION

Using multiplex RTqPCR-based models in urine sediment it is possible to improve the current diagnostic method of choice (PCA3) to differentiate between benign HGPIN and PCa cases.

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.

Urine TMPRSS2:ERG Plus PCA3 for Individualized Prostate Cancer Risk Assessment

BACKGROUND

TMPRSS2:ERG (T2:ERG) and prostate cancer antigen 3 (PCA3) are the most advanced urine-based prostate cancer (PCa) early detection biomarkers.

OBJECTIVE

Validate logistic regression models, termed Mi-Prostate Score (MiPS), that incorporate serum prostate-specific antigen (PSA; or the multivariate Prostate Cancer Prevention Trial risk calculator version 1.0 [PCPTrc]) and urine T2:ERG and PCA3 scores for predicting PCa and high-grade PCa on biopsy.

DESIGN, SETTING, AND PARTICIPANTS

T2:ERG and PCA3 scores were generated using clinical-grade transcription-mediated amplification assays. Pretrained MiPS models were applied to a validation cohort of whole urine samples prospectively collected after digital rectal examination from 1244 men presenting for biopsy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Area under the curve (AUC) was used to compare the performance of serum PSA (or the PCPTrc) alone and MiPS models. Decision curve analysis (DCA) was used to assess clinical benefit.

RESULTS AND LIMITATIONS

Among informative validation cohort samples (n=1225 [98%], 80% from patients presenting for initial biopsy), models incorporating T2:ERG had significantly greater AUC than PSA (or PCPTrc) for predicting PCa (PSA: 0.693 vs 0.585; PCPTrc: 0.718 vs 0.639; both p<0.001) or high-grade (Gleason score >6) PCa on biopsy (PSA: 0.729 vs 0.651, p<0.001; PCPTrc: 0.754 vs 0.707, p=0.006). MiPS models incorporating T2:ERG score had significantly greater AUC (all p<0.001) than models incorporating only PCA3 plus PSA (or PCPTrc or high-grade cancer PCPTrc [PCPThg]). DCA demonstrated net benefit of the MiPS_PCPTrc (or MiPS_PCPThg) model compared with the PCPTrc (or PCPThg) across relevant threshold probabilities.

CONCLUSIONS

Incorporating urine T2:ERG and PCA3 scores improves the performance of serum PSA (or PCPTrc) for predicting PCa and high-grade PCa on biopsy.

PATIENT SUMMARY

Incorporation of two prostate cancer (PCa)-specific biomarkers (TMPRSS2:ERG and PCA3) measured in the urine improved on serum prostate-specific antigen (or a multivariate risk calculator) for predicting the presence of PCa and high-grade PCa on biopsy. A combined test, Mi-Prostate Score, uses models validated in this study and is clinically available to provide individualized risk estimates.