Urinary PCA3 to predict prostate cancer in a cohort of 1015 patients

(1)

Disponibleenlignesur

ScienceDirect

www.sciencedirect.com

ORIGINAL ARTICLE

Urinary PCA3 to predict prostate cancer in a cohort of 1015 patients

Test urinaire PCA3 et diagnostic du cancer prostatique : étude à partir de 1015 patients

V. Vlaeminck-Guillem

^a^,∗,^b

, M. Devonec

^c^,^d

, D. Champetier

^c

, M. Decaussin-Petrucci

^b^,^d^,^e

, P. Paparel

^c^,^d

, P. Perrin

^c^,^d

, A. Rufﬁon

^b^,^c^,^d

aUnitéd’oncologiemoléculaireettransfert,servicedebiochimieetbiologiemoléculaire sud,centrehospitalierLyon-Sud,hospicescivilsdeLyon,cheminduGrand-Revoyet,69495 Pierre-Bénite,France

bInserm1052CNRS5286,centrederechercheencancérologiedeLyon—centreLéon-Bérard, universitéLyon1,69373Lyoncedex08,France

cServiced’urologie,centrehospitalierLyon-Sud,hospicescivilsdeLyon,chemindu Grand-Revoyet,69495Pierre-Bénite,France

dFacultédemédecineLyon-Sud,universitéLyon 1,cheminduPetit-Revoyet,69921Oullins cedex,France

eLaboratoired’anatomieetcytologiepathologiques,centrehospitalierLyon-Sud,hospices civilsdeLyon,cheminduGrand-Revoyet,69495Pierre-Bénite,France

Received2July2015;accepted10October2015 Availableonline14November2015

KEYWORDS Prostatecancer;

Diagnosis;

Prostatebiopsies;

Prediction;

PCA3;

Urinarytest

Summary

Aim.—ToevaluatetheperformanceofurinaryPCA3testtopredictprostatebiopsyoutcome inalargeFrenchcohort.

Patientsandmethods.—Aurinesamplewasprospectivelyobtainedfrom1015patientsunder- goingprostatebiopsiestodeterminethePCA3score.ThepredictivevalueofPCA3wasexplored usingreceiveroperatingcharacteristiccurveanalysis(ROC),multivariablelogisticregression analysisanddecisioncurveanalysis.

DOIoforiginalarticle:http://dx.doi.org/10.1016/j.purol.2015.08.005.

∗Correspondingauthor.

E-mailaddress:virginie.vlaeminck-guillem@univ-lyon1.fr(V.Vlaeminck-Guillem).

http://dx.doi.org/10.1016/j.purol.2015.10.006

(2)

Results.—ThemedianPCA3scorewassignificantlyhigherinpatientswithpositivebiopsies.The PCA3scoreAUCwas0.76(0.73—0.79),significantlyhigherthanthatofPSA(0.55;0.51—0.58).At thecutoffof35,sensitivitywas68%,specificity71%,positiveandnegativepredictivevalues67%

and71%,andaccuracy69%.Usingmultivariateanalysis,PCA3scoreappearedasanindependent predictorofbiopsyoutcomeanditsadditiontoabasemodelincludingusualclinicobiological parametersresultedinasigniﬁcantincreaseinpredictiveaccuracy.Atthecutoffof20,about 1/2oftheultimatelyunnecessarybiopsieswouldhavebeenavoidedwhileignoring7%ofcancers withGleasonscore≥7.PCA3scoredidnotcorrelatewithGleasonscorebutdidcorrelatewith tumorvolume(proportionofpositivecores).

Conclusion.—UrinaryPCA3isausefultestwithhighdiagnosticperformancesforearlyprostate cancerdiagnosis.Itscorrelationwithcanceraggressivenessseemsratherrepresentedbyalink toprostatevolumethanGleasonscore.

Levelofevidence.— 5.

MOTSCLÉS Cancerdela prostate; Diagnostic; Biopsies prostatiques; Prédiction; PCA3; Testurinaire

Résumé

But.—ÉvaluerlacapacitédutesturinairePCA3 àprédirelerésultatdesbiopsiesprostatiques dansunelargecohorteissueducentrehospitalierLyonSud.

Patientsetméthodes.—LescorePCA3 aétédéterminéprospectivementchez1015 patients adresséspourbiopsiesprostatiques.LacapacitéprédictiveduscorePCA3aétéévaluéeparla comparaisondesairessouslescourbesROC,demodèlesderégressionlogistiqueetuneanalyse par« decisioncurveanalysis »(DCA).

Résultats.—Le scorePCA3 médianétaitsigniﬁcativementplusélevéchezlespatients avec biopsiespositives.L’AUCétaitde0,76,signiﬁcativementplusélevéequecelleduPSAà0,55.

Auseuilde35,lasensibilitéétaitde68%,laspécificitéde71 %,lesvaleursprédictivespositive etnégativede67 %et71%,etl’efficiencede69%.Enanalysemultivariée,lescorePCA3était prédicteurindépendantdurésultatdesbiopsiesetsonadditionàunmodèledebasecomportant lesdonnéesclinicobiologiquesclassiquesapportaitungaindiagnostiquesignificatif.Auseuilde 20,prèsdelamoitiédesbiopsiesaposterioriinutilesauraientétéévitées,toutenayantignoré 7%descancersavecscoredeGleason ≥7.LescorePCA3n’apparaissaitpascorréléauscore deGleason,maisétaitbiencorréléauvolumetumoral(évaluéparlaproportiondecarottes envahies).

Conclusion.—LetesturinairePCA3 présentedesperformancesdiagnostiquesélevéespourle diagnosticprécoceduCaP.Sacorrélationavecl’agressivitéducancers’exprimeàtraversle volumetumoralplusqueparlescoredeGleason.

Niveaudepreuve.— 5.

Introduction

The first urine test for the quantitative assessment of prostatecancergene 3 (PCA3)RNAtranscripts inpatients withsuspectedprostate cancer(PCa) waspublishedmore than 10 years ago [1]. The PCA3 RNA product is almost exclusivelyexpressedincancerousprostatetissue.Itisnot expressedin othertissues andonly veryweaklyexpressed inhealthyprostatetissueorinnon-malignantprostaticdis- eases[1—3].ThediscoveryanddiagnosticuseofPCA3came aboutinresponsetothelackofspecificityofserumprostate- specificantigen(PSA)testingforthediagnosisofPCa.

To date, approximately 100 studies, involving cumu- latively close to 30,000 patients, have been conducted to evaluate urinary PCA3 RNA measurement (PCA3 test)

in clinical practice [4—6]. The PCA3 test was approved for diagnostic purposes by the United States Food and DrugAdministrationin2012,asadecisionalaidforrepeat prostatebiopsyinpatientsagedatleast50 yearswhohave had one or more previous negative biopsies. In France, as of this writing, the PCA3 test is only available for clinical research studies or in the setting of a voluntary, patient-payed diagnostic process. Published clinical studies, variable in scientiﬁc quality, tend to show that the urinaryPCA3testcanbeofsigniﬁcantvaluewhendeciding whetherornottoperformprostatebiopsy.Incontrasttothe serumPSA,whichisaffectedbyprostatevolume,thePCA3 scoredoesnotincreaseinthepresenceofanon-malignant prostatic disease [7]. It does however correlate with the risk ofpositivebiopsyanditsusemayreduce thenumber

(3)

ofultimately-negative(andthus,aposterioriunnecessary) biopsiesbyhalftotwo-third[4—6].Correlationsareassumed toexistbetweenthePCA3scoreandhistoprognosticcriteria identiﬁedonbiopsyorprostatectomyspecimens.

Thepurposeofthepresentworkistoreportourexperi- encewiththediagnosticandprognosticperformanceofthe urinaryPCA3testinalargecohortofpatientsreferredfor prostatebiopsyfollowingasuspicionofprostatecancer.

Patients and methods Patients

Allpatientsreferredtooururologydepartmentbetween20 December 2007 and5 May 2014for prostatebiopsy were consecutively included in this prospective, single-center study. Reasons for referral were serum PSA ≥ 4ng/mL and/oranabnormaldigitalrectalexamination(DRE)and/or afamilyhistoryofPCa.Patientswithapersonalhistoryof PCawereexcluded,butthosewithahistoryofoneormore negativeprostatebiopsieswereincluded.Onehundredand sixtyoftheincludedpatientshadbeenincludedinanearlier study[8].Allpatientsprovidedwritteninformedconsent.

After the collection of urine samples for the PCA3 test, the patients underwent a prostate biopsy series in accordance with the recommendations of the European Association of Urology, i.e., at least six corestaken from eachlobeundertransrectalultrasoundguidance,thislatter permittingalsoanevaluationofprostate volume.The fol- lowing anatomopathological data were recorded: Gleason score,percentageofpositivecores,percentageoftumorous prostatictissue,unilateral or bilateral involvement,pres- enceorabsenceofperineuralinvasion,presenceorabsence ofextracapsularextension.

Urine samples and urinary PCA3 test

First-catchurinesamples(25—30mL) werecollectedafter standardizedDRE[9].Thesampleswereimmediatelytrans- ferredtospeciﬁcspecimentubes(ProgensaUrineSpecimen TransportKit,Gen-Probe),andstoredat−20^◦Cuntilthetest couldbeperformed. The PCA3test(Progensa PCA3assay, DTS400system, Hologic Gen-Probe)wasperformed at the hospital’s biochemistry service as per the manufacturer’s recommendations. The PCA3 score was calculated as the ratioofPCA3toPSARNAcopies,multipliedby1000.When less than10,000 copies of PSAmRNAwere detected, the urinesamplewasconsideredasnon-informative.

Statistical analyses

Thenormaldistributionofquantitativevariableswasveri- ﬁedtopermittheircomparisonusingtheStudent’st-test.

Proportions for qualitative variableswere comparedusing theChi²test. Correlations betweenquantitative variables wereidentiﬁedusinglinearregression.

ROC curvewasestablished for PCA3scoretocalculate theareaunderthecurve(AUC).Foragiventhreshold,test performance wasevaluated in terms of sensitivity, speci- ﬁcity,positiveandnegativepredictivevalues,andaccuracy (rate of correctly-classiﬁed patients) by comparing PCA3

scores to biopsy histological results. The contribution of thePCA3scoreinrelationtoexistingclinicalandbiological datawasevaluatedinmultivariate(nestedlogisticregres- sionmodels)anddecisioncurveanalyses(DCA).Calculations wereperformedusingStataStatisticalSoftwareRelease 11 (StataCorp,CollegeStation,Texas,USA).AP-value< 0.05 wasconsideredstatisticallysigniﬁcant.

Results

Baseline characteristics

Inthestudyperiod,1029 patientshadaurinaryPCA3test before undergoing prostate biopsy for suspicion of PCa.

Urinesampleswereinformativefor1015 (98.6%)ofthem.

Thecharacteristicsofthe14 patientswithnon-informative samples did not differ from those of the other patients exceptforahigherrateof5␣-reductaseinhibitoruse:21%

vs2% (P=0.003).Furtheranalyseswerethus performedin the1015 patientswithinformativesamples(Table1).Sig- niﬁcant differences between the 480 (47%) patients with positivebiopsiesandthe 535(53%)withnegativebiopsies were,fortheformer: olderage, higherserumPSA levels, lower prostate volume, less frequent history of negative biopsies,DREmorefrequentlysuspicious(Table1).

Diagnostic performance of the urinary PCA3 test

ThemedianPCA3scorewassignificantlyhigherinpatients withpositivebiopsies,i.e.,53vs20(P<0.0001)inpatients withnegative biopsies (Table 1), and the risk of positive biopsyincreasedwiththePCA3score(Fig.1).TheAUCof the PCA3 score was significantly higher than that of the serumPSA,respectively0.76(95%CI:0.73—0.79)and0.55 (0.51—0.58)(Fig.2).Thecutoffof35,usuallyusedinthelit- erature,wasindeedagoodcompromisebetweensensitivity (68%)andspecificity(71%)foranaccuracyof69%(Fig.2).

Therisk ofpositivebiopsy (67%)inthe482 (47%)patients withPCA3score ≥ 35wasmorethantwicethatofthe533 patientswithPCA3score< 35(P<0.001).

ThediagnosticperformanceofthePCA3testwassimilar inpatients withor without ahistory ofnegativebiopsies,

Figure1. IncreasingriskofpositivebiopsieswiththeurinaryPCA3 score.

(4)

Table1 Baselinecharacteristicsofthe1015 patientswithinformativeurinesamples,andcorrelationswithpresence ofcanceronbiopsies.Forquantitativevariables,median, IQR(interquartilerange),meanandstandarddeviationare indicated.

Wholecohort Patientswith negativebiopsies

Patientswith positivebiopsies

Signiﬁcativity(P)

Numberofpatients n=1015 n=535(53%) n=480(47%)

Medianage (n=1015)

64 years(59—69) (mean:64±7)

63 years(58—67) (mean:63±6)

66 years(61—70) (mean:66±7)

<0.0001 Priornegativebiopsies

0 n=825(81%) n=406(76%) n=419(87%) <0.001

1 n=144(14%) n=95(18%) n=49(10%)

2 n=31(3%) n=22(4%) n=9(2%)

≥ 3 n=15(1%) n=12(2%) n=3(1%) Previousadministrationof5˛-reductaseinhibitors

Yes n=20(2%) n=11(2%) n=9(2%) =0.836

No n=995(98%) n=524(98%) n=471(98%)

Digitalrectalexamination

Suspicious n=145(14%) n=41(8%) n=104(22%) <0.001

Notsuspicious n=870(86%) n=494(92%) n=376(78%) Medianprostatevolume

(n=1003)

40mL(29—54) (mean:44±21)

45mL(32—60) (mean:49±23)

35mL(26—48) (mean:38±17)

<0.0001 Mediannumberofbiopsy

cores

12(12—12) (mean:12±1)

=1.000 TotalserumPSA

Median 6.6ng/mL

(5—9.4)

(mean6.2±4.3)

6.4ng/mL (4.9—9)

(mean:7.6±4.8)

6.8ng/mL (5.1—10) (mean:

16.4±57.2)

=0.0004

< 2.5ng/mL n=25(2%) n=17(8%) n=8(2%) =0.018

2.5—3.99ng/mL n=67(7%) n=36(7%) n=376(6%)

4—9.99ng/mL n=697(69%) n=382(71%) n=315(66%)

≥ 10ng/mL n=226(22%) n=100(19%) n=126(26%)

MedianurinaryPCA3score 32(16—66) (mean:57±67)

20(11—41) (mean:35±47)

53(28—100) (mean:81±78)

<0.0001

i.e.,AUCsof0.74(0.67—0.82)and0.76(0.73—0.79)respectively,P=0.643. It differedhowever as afunction of PSA values.Whether thePSA valueswere between2.5 and4, between4and10,orgreaterthan10ng/mL,thediagnostic performanceofthePCA3testwashomogenous,withAUCs between0.73and0.76.However,in thegroupofpatients withPSA < 2.5ng/mL, performance wasparticularlyhigh withanAUCof0.95(0.85—1.00).

Integration of the PCA3 score in a nomogram

Age,DREﬁndings(suspiciousvsnonsuspicious),historyof negativeprostate biopsies(nohistoryvsat leastoneneg- ative biopsy series), prostate volume, history of physical treatmentforbenignprostatehyperplasia(BPH),serumPSA andPCA3scorewereallpredictivefactorsofbiopsyresults inunivariateanalysis(Table2).Theywereallindependently predictiveinmultivariateanalysisalso,exceptforphysical treatmentforBPH.Alltheclinicalandbiologicalvariables predictiveofbiopsyresultsinmultivariateanalysis(except the PCA3 score) were integrated into a base predictive model,the AUCof which was0.75(0.72—0.78) (Table2).

When the PCA3 score was added tothe base model, the AUCincreasedsigniﬁcantlyto0.80(0.77—0.83)(P<0.001) (Table2).TocomparethenetpredictivebeneﬁtofthePCA3

test, a decision curve analysis (DCA) wasperformed. The modelincorporatingthePCA3scoreproducedapredictive beneﬁtgreaterthanthatofthebasemodel(Fig.3).

Prediction of prostate cancer aggressiveness

Inthe480 patientswithpositivebiopsies,themedianPCA3 score did not differ signiﬁcantly between the 225 (47%) patients withGleason 6 scoreand the255 (53%) patients withGleasonscore≥7(Table3).Equally,therewerenodif- ferencesaccordingtothepresenceorabsenceofperineural invasion or extracapsular extension (Table 3).Conversely, PCA3scorewassigniﬁcantlyhigherwhenlesionswerebilat- eral,when≥ 33%ofcoreswerepositiveorwhen≥ 10%of prostatetissuewastumorous(Table3).

An issue in PCadiagnosis is toonly identifysigniﬁcant cancers.Usingacut-offof20forthePCA3scoretoperforma biopsy,332(33%)ofthepatientsinthisstudywouldhavenot undergonethebiopsy.Athirdoftheultimatelyunnecessary biopsieswouldhavebeenavoided,but67ofthe480cancers (14%)wouldhavemissed.Amongthose67cancerswithPCA3 score<20,17wereGleason 7and2wereGleason 8.Among the48 unidentiﬁedGleason 6cases,onlyonehadarateof positivecores ≥ 33%.Amongthe67 missedcancercases, 14hadabnormalDREand/orPSAlevel ≥ 10ng/mL.

(5)

Figure2. DiagnosticperformancesoftheurinaryPCA3scoreand comparisonwithserumPSA.AUC:areaundercurveROC;95%CI:

95%confidenceinterval;Se:sensitivity;Spe:specificity;PPV:posi- tivepredictivevalue;NPV:negativepredictivevalue;Acc:accuracy (proportionofcorrectly-classifiedpatients).

0.000.100.200.300.400.50

0 20 40 60 80

Seuil de probabilité de biopsies positives en %

s u o t n

u c u a

Net beneﬁt

Probabilitythresholdfor posive biopsies (%)

noneBase model all

Base model + ¨PCA3 score

Figure3. EvaluationoftheabilityofthePCA3scoretopredict positivebiopsies(netbeneﬁt)usingdecisioncurveanalysis(DCA);

basemodel:age,digitalrectalexamination,previousnegativebiop- sies,prostatevolume,serum PSA.DCAexaminedthetheoretical relationshipbetweenthethresholdprobabilityoftheoutcomeof positiveprostatebiopsiesandtherelativevalueoffalse-positive andfalse-negativeresults.Here,we estimatedthemagnitudeof beneﬁtresultingfromalteringclinicalmanagementinpatientswith differentthresholdprobabilitiesofpositivebiopsies.

Table2 Multivariateanalyses evaluatingtheabilityof clinicobiologicalvariablestopredictprostate biopsyoutcome andcomparisonwiththeadditionofurinaryPCA3score(n = 1015 patients).

Univariateanalysis Multivariateanalysis

Basemodel Basemodel

+PCA3score OR

(IC95%)

P AUC OR

(IC95%)

P OR

(IC95%)

P

Age 1.06

(1.04—1.08)

< 0.001 61.6%

(58—65)

1.07 (1.05—1.10)

< 0.001 1.05 (1.02—1.07)

< 0.001 Previousbiopsies 0.46

(0.33—0.64)

< 0.001 55.7%

(53—58)

0.45 (0.30—0.67)

< 0.001 0.48 (0.31—0.75)

0.001 Prostatevolume 0.97

(0.96—0.98)

< 0.001 65.5%

(62—69)

0.97 (0.96—0.97)

< 0.001 0.97 (0.96—0.97)

< 0.001 Digitalrectal

examination

3.33 (2.27—4.90)

< 0.001 57.0%

(55—59)

2.15 (1.39—3.34)

0.001 2.03

(1.31—3.15)

0.002

SerumPSA 1.04

(1.02—1.06)

< 0.001 54.9%

(51—58)

1.07 (1.02—1.12)

0.005 1.07

(1.02—1.12)

0.006

PCA3score 1.02

(1.01—1.02)

< 0.001 75.8%

(73—79)

— — 1.01

(1.01—1.02)

< 0.001 Prediction

accuracy^a

74.6%

(72—78)

80.1%

(77—82) Increasein

performances

+5.5%

P < 0.001 OR:oddsratio.

a EstimationusingtheAUC(%).

(6)

Table3 PathologicalcharacteristicsoftheprostatebiopsiesandcorrelationswiththeurinaryPCA3score.

Pathologicalcriteria PCA3Score

Median(IQR)(P)

Gleasonscore =0.674

6 n=225(47%) n=225(47%) 48(26—96)

7 n=208(43%) n=255(53%) 60(32—108)

8 n=35(7%)

9 n=12(3%)

Proportionofinvadedcores =0.0001

Median(IQR) 25%(14—48)

< 33% n=264(55%) 45(23—85)

≥ 33% n=216(45%) 68(39—132)

Proportionofinvadedtissue =0.002

Median(IQR) 6%(2—14)

< 10% n=307(64%) 49(24—93)

≥ 10% n=171(36%) 65(36—129)

Laterality <0.0001

Unilateral n=263(55%) 42(23—82)

Bilateral n=217(45%) 72(42—132)

Perineuralinvolvement =0.863

No n=389(81%) 51(28—97)

Yes n=91(19%) 61(29—110)

Extracapsularextension =0.200

No n=464(97%) 52(28—99)

Yes n=16(3%) 80(25—141)

IQR:interquartilerange.

Discussion

Inthepresent study,weevaluatedtheabilityofthePCA3 urinetest topredict prostate biopsy results in morethan 1000 patients. Toourknowledge, thisisthe largeststudy of itskind ever performed in France.Our results conﬁrm previouslypublisheddataconcerningtheurinaryPCA3test, particularlyitsfunction asapredictorof biopsyoutcome, independentof otherclinical andbiologicalvariables rou- tinely used in clinical practice to decide whether or not toperformabiopsy. We demonstratedhere,both in mul- tivariatelogisticregressionandinDCA,thattheadditionof thePCA3scoretotheusualclinicalandbiologicalvariables providesasigniﬁcantdiagnosticgain.Themainlimitofour studyisitssingle-centernature;allofthepatientsusedin thisstudy weretreated in the same urology department.

Wedoemphasize however thatthe referralsfor the1015 patientsweremadeby20 differenturologistswithdiffer- entpractices.Forexample,therateofpositivebiopsyfor thesix physicians whoreferred at least 75 patients each rangedfrom36to65%.Wethinkthereforethatourcohort wassufﬁcientlydiverseandrepresentativeofalargerange ofsensibilitiesinurology.

TheoveralldiagnosticperformanceofthePCA3testthat wereporthere,withanAUCof0.76,isperfectlycoherent withthat reportedin the literature [4—6]. In ourexperi- ence, the cut-off of 35 has indeed proven to be a good compromisebetweensensitivity(68%)andspeciﬁcity(71%).

Two-thirdsof ourpatients withPCA3score ≥ 35hadpos- itivebiopsiescomparedtolessthanathirdforthosewith

score < 35.However,ourfindingsalsoclearlyindicatethat ahighPCA3scoreisnotnecessarilysynonymouswithcan- cer (falsepositives) andthat low oreven verylowscores are not necessarily synonymous withthe absence of cancer (false negatives).It underlinesthe importanceto use the PCA3score inconjunction withthe usual clinical and biological findings, andevenconsider itsuse aspart of a specific nomogram[10,11]. Fivetotenpercentof PCado not express the PCA3RNA product [2,12], which explains a certain numberof false negatives. In contrast,there is currently noclearlyidentifiedmechanism toexplainfalse positives,butpatientsshouldbecloselymonitored[13—15].

Wealsoconfirmedthattheriskofpositivebiopsiesincreases asthePCA3scoreincreases(Fig.1). Theuse ofa thresh- oldisthus anarbitrary approachthat mustfindabalance betweentwocontradictoryimperatives:avoidingunneces- sarybiopsieswheneverpossible(toreducepublichealthcare costs,morbidity,psychologicalimpactsforthepatient)and not missingtoo manycancers, particularlythosethat are life-threatening.ThePCA3thresholdof20maybeabetter compromisethan35;withitsa-thirdof ourbiopsies(i.e., halfoftheultimatelyunnecessarybiopsies)couldhavebeen avoided.However,theabsenceofcorrelationbetweenthe PCA3scoreandtheGleasonscoreonbiopsiedtissue,atleast inourstudy(seeinfra),isanobstacletoimprovetheratio ofavoidedbiopsiestomissedsignificantcancers.Costeffec- tivenessstudiesareneededtodetermineifthegeneralized useofthePCA3testcaneffectivelyreducehealthcarecosts by loweringthenumberof unnecessarybiopsies andtheir associatedcomplications.

(7)

Inourlargecohort,thePCA3testwasrobust,particularly withmorethan98%ofinformativesamples.Thishighrateis usualwiththiscommercialkit,whichincludesatargetRNA selectionstepbeforeampliﬁcation[9].Inourstudy,onlythe useof5␣-reductaseinhibitorsappearedtoreducetherate ofinformativesamples,whichislogicalsincetheseagents induce a reduction in the expression of PSA RNA. How- ever,wheninformativesamplesareretrievedfrompatients taking5␣-reductaseinhibitors,thediagnosticperformance of the PCA3test does not appear tobe affected, aswas demonstrated in the REDUCE trial on dutasteride for PCa prevention[16].

AlsoillustratingtherobustnessofthePCA3testwasthe lack ofinfluenceof theusualclinical variablesonitsper- formance,whichremainedgoodregardlessofage,prostate volume,DREresults,orthepresenceorabsenceofahistory ofnegativebiopsies.Consideringthesefindings,itappears to usthat restricting the availability of the PCA3 test to onlythosepatientswithahistoryofnegativebiopsiesisnot justified; this positionis additionally strengthened by the results ofrecent studies onpatients undergoingan initial prostatebiopsy[11,17].IncontrasttoPSAlevels,thePCA3 scoredoesnotincreasewithprostatevolume.Furthermore, in our study, we detected an inverse correlation wherein the PCA3 score increases as prostate volume decreases.

This reflects essentiallythehigherfrequency of cancerin patients with low prostate volume (PCA3 being a cancer marker) in opposition to the higher frequency of BPH in patientswithhighprostatevolume.Theonlyfactorthathad aninfluenceonPCA3testperformanceinourstudywasthe PSAlevelitself.Moreprecisely,thediagnosticperformance of the PCA3 test was stable across all PSA levelsgreater than 2.5ng/mL (AUCsbetween 0.73 and0.76), but under that threshold,itimproved (AUCof 0.95). Thesepatients withPSA<2.5ng/mLweremainlyreferredforbiopsybased solelyonaconfirmedfamilyhistoryofprostatecancer.Thus, thePCA3testappearstobeparticularlyadvantageousinthis specificpopulation,whereitsaccuracyhasthepotentialto limitrepeatedandunnecessarybiopsiesinfrequentlyyoung patients.

The diagnosticperformanceofthePCA3test prompted the clinicianstoassess itsinterest for prognosis. Correla- tions between the PCA3 score and the Gleason score on biopsieshavebeensuggested[4],buttheliteratureremains contradictory on this question. In the present study, we found no correlations between the PCA3 score and the Gleason score; our negative result can be explained nei- ther by a lack of statistical power nor by differences in studied populations (similar proportions of patients with Gleason scores<or ≥ 7). Wenote as wellthat in an ear- lier work, our team found no correlations between PCA3 scores and Gleason scores calculated onradical prostatectomy specimens (study on 154 patients from the same sourcecohortashere)[18].Additionally,earlyhistological studiesdidnotdemonstrate anylinks betweenPCA3gene expressionandcancerdifferentiation[2,3,19].Incontrast, studies on prostatectomy specimens have demonstrated associations between the PCA3 score and tumor volume [18,20],ashavebiopsystudiessuchasthepresentvia the proportions of positive cores and tumorous prostatic tis- sue.

Conclusion

Thepresent studyinvolving morethan1000 patientscon- firmedperformancedataontheurinaryPCA3test forthe prediction of prostate biopsy results. The classic clinical andbiologicalvariables suchasage, DRE findings,history of negativebiopsies, prostate volumeor serumPSA level didnot influence theperformance of the test. Additional studiesareneededtoevaluatetheinterestofpairing(simul- taneouslyor sequentially) the PCA3 test with MRI of the prostate,whichisincreasinglyusedforthediagnosisofPCa andthe assessment of itsaggressiveness. The benefits of avoidingunnecessarybiopsiesisamajorissue.Wheneval- uatedasapartofdecisionalmodelsforrepeatbiopsieson ahistoryofnegativebiopsies,theintroductionofthePCA3 testinclinicalpracticecouldsavebetweenD1.7and5mil- lionaccordingtothecostsrelatedtobiopsycomplications [21].The costofcancersthatmayescapedetectionwhen thePCA3testisusedtodecideonabiopsyshouldbeinte- gratedintothesecalculations.Finally,theimpactofthetest inthediagnosticprocessoverallremainstobedetermined.

Towardthis,anevaluationisunderwayaspartofasupport program for costly innovative technologiesfunded by the FrenchNationalCancerInstitute(INCa).

Acknowledgments

We thank Doctors M. Vinet, E. Briant, N. Gobeaux, J.L.

Campos-Fernandez,E. Adam,S. Genevoix, C. DeVendin, R. Lardon,G. Pic,F.X. Buttin,F. Lalloue,M. GorisandX.

Borgnatfortheiraidinenrollingpatients,Ms.M. Cottancin andMs.B. Grangierfortheirtechnicalassistance,andMs.

M. Dupuisforherassistancewithdatacollection.

Disclosure of interest

Theauthorsdeclarethattheyhavenocompetinginterest.

References

[1]HesselsD,KleinGunnewiekJM,vanOortI,KarthausHF,van LeendersGJ,vanBalkenB,etal.DD3(PCA3)-basedmolecular urineanalysisfor thediagnosis ofprostatecancer.EurUrol 2003;44:8—15.

[2]Bussemakers MJ, van Bokhoven A, Verhaegh GW, Smit FP, KarthausHF,SchalkenJA,etal.DD3:anewprostate-speciﬁc gene, highly overexpressed in prostate cancer. Cancer Res 1999;59:5975—9.

[3]deKokJB,VerhaeghGW,RoelofsRW,HesselsD,KiemeneyLA, AaldersTW, et al. DD3(PCA3), a very sensitiveand speciﬁc markertodetectprostatetumors.CancerRes2002;62:2695—8.

[4]Auprich M, Bjartell A, Chun FK, de la Taille A, Freedland SJ, Haese A, et al. Contemporary role of prostate cancer antigen 3 in the management of prostate cancer.Eur Urol 2011;60:1045—54.

[5]BradleyLA,PalomakiG,GutmanS,SamsonDJ,AronsonN.PCA3 testing for the diagnosis and management ofprostate cancer.AHRQcomparativeeffectivenessreviews.Rockville(MD):

AgencyforHealthcareResearchandQuality(US);2013.

[6]Vlaeminck-GuillemV,RufﬁonA,AndreJ.ValueofurinaryPCA3 testforprostatecancerdiagnosis.ProgUrol2008;18:259—65.

(8)

[7]Vlaeminck-Guillem V, Bandel M, Cottancin M, Rodriguez- LafrasseC,BohbotJM,SednaouiP.Chronicprostatitisdoesnot inﬂuenceurinaryPCA3score.Prostate2012;72:549—54.

[8]Vlaeminck-Guillem V, Devonec M, Paparel P,Champetier D, Campos-FernandesJL,PerrinP,etal.ValueofPCA3urinarytest forprostatebiopsydecision:theLyon-SudUniversityHospital experience.AnnBiolClin2011;69:31—9.

[9]GroskopfJ,Aubin SM,DerasIL,Blase A,BodrugS, ClarkC, et al.APTIMAPCA3 molecularurinetest: developmentofa methodtoaidinthediagnosisofprostatecancer.ClinChem 2006;52:1089—95.

[10]ChunFK,delaTailleA,vanPoppelH,MarbergerM,StenzlA, MuldersPF,etal.ProstateCancerGene3(PCA3):development andinternalvalidationofanovelbiopsynomogram.EurUrol 2009;56:659—68.

[11]Rufﬁon A, Devonec M,Champetier D,Decaussin-Petrucci M, Rodriguez-LafrasseC,PaparelP,etal.PCA3andPCA3-based nomogramsimprovediagnosticaccuracyinpatientsundergoing ﬁrstprostatebiopsy.IntJMolSci2013;14:17767—80.

[12]Floriano-Sanchez E, Cardenas-Rodriguez N, Castro-Marin M, Alvarez-Grave P, Lara-Padilla E. DD3(PCA3) gene expression in cancer and prostatic hyperplasia. Clin Invest Med 2009;32:E258.

[13]Remzi M,Haese A, VanPoppel H, DeLa TailleA, Stenzl A, Hennenlotter J, et al. Follow-up of men withan elevated PCA3 score and a negative biopsy: does an elevated PCA3 scoreindeedpredictthepresenceofprostatecancer?BJUInt 2010;106:1138—42.

[14]Roobol MJ, Schroder FH, van Leenders GL, Hessels D, van den Bergh RC, Wolters T, et al. Performance of Prostate Cancer Antigen 3 (PCA3) and prostate-speciﬁc antigen in

prescreenedmen:reproducibility anddetection characteris- ticsforprostatecancerpatientswithhighPCA3Scores(≥100).

EurUrol2010;58:893—9.

[15]SchroderFH,VenderbosLD,vandenBerghRC,HesselsD,van LeendersGJ,vanLeeuwenPJ,etal.Prostatecancerantigen 3:diagnosticoutcomesinmenpresentingwithurinaryprostate cancerantigen 3scores≥100.Urology2014;83:613—6.

[16]Aubin SM,Reid J,Sarno MJ,BlaseA, Aussie J, Rittenhouse H, et al. Prostate Cancer Gene 3 Score predicts prostate biopsyoutcomein menreceivingdutasteridefor prevention of prostatecancer: resultsfrom theREDUCE Trial. Urology 2011;78:380—5.

[17]Chevli KK, Duff M, Walter P, Yu C, Capuder B, Elshafei A, et al.Urinary PCA3 as a predictorfor prostate cancerin a cohortof3073 menundergoinginitialprostatebiopsy.JUrol 2014;191:1743—8.

[18]TallonL,LuangphakdyD,RufﬁonA,ColombelM,DevonecM, ChampetierD,etal.ComparativeevaluationofurinaryPCA3 andTMPRSS2:ERGscoresandserumPHIinpredictingprostate canceraggressiveness.IntJMolSci2014;15:13299—316.

[19]BalcerczakE,MirowskiM, SasorA, WierzbickiR. Expression ofp65,DD3andc-erbB2genesinprostatecancer.Neoplasma 2003;50:97—101.

[20]NakanishiH,GroskopfJ,FritscheHA,BhadkamkarV,BlaseA, KumarSV,etal.PCA3molecular urineassaycorrelateswith prostatecancertumorvolume:implicationinselectingcandi- datesforactivesurveillance.JUrol2008;179:1804—9.

[21]MalavaudB,CussenotO,MottetN,RozetF,RufﬁonA,SmetsL, etal.ImpactofadoptionofadecisionalgorithmincludingPCA3 forrepeatbiopsyonthecostsforprostatecancerdiagnosisin France.JMedEcon2013;16:358—63.