**PPT Budapest JD - Cancer Rose€¦ · Prescrire, Cochrane Group, SwissMedicalBoard,...
Transcript of **PPT Budapest JD - Cancer Rose€¦ · Prescrire, Cochrane Group, SwissMedicalBoard,...
Efficiency evaluation ofcancerscreeningis based on:
Age-adjustedincidenceof
advanced cancersshould decrease after
introductionofscreening.
Specific cancer-mortalityshould decrease moreinareaswhere screeningiseffective,than inareaswhere there is noorfew
screening
(ifmanagementofpatientsis similar).
Firstrandom trialsadopted distinctivemethods which led toexagerate theefficiency ofscreening.
Methodologicalflaws inthe
results analysis
Bestresults inthemost
doubtful trials.
(bias)
Cochranewarned aboutbiases inyear2000,beforescreeningwas
putinwidespread use
inFrance
(in2004)
Randomized trialson500000women,failed toshowany mortalitydecrease (risk todie)duetoscreening
Greatdecrease of
Mortality is advanced (-20%) *Decrease oftherateof
mastectomies.
*Decrease ofadvancedforms ofcancer.
Problem is :screeningofbreast cancersis often presented inavery
positiveway.
Serious authors disagree with these assertions:frenchmedical journalPrescrire,CochraneGroup,Swiss Medical Board,recent international
studies.
BUT
BUT
Other claimed
results :
Thekeyelements ofasuccessfulscreeningprogramis adecrease ofmortality and
advanced tumors.
These objectifshavenotbeenreached.
Mortality bybreastcancerdid notdecreasemoreinareaswherewomen havebeeenscreened,since 1980
Decrease is notdifferentinscreened andinnotscreened women.
Strong increase ofthenumber ofsmall
tumors,
with nodecrease ofmortality.
Inreallive,after 30years ofscreening,
key points
incidenceofadvanced
andmetastatic breast
cancerremained
stable.
Onethird toonehalf ofallscreened breastcancerswouldnever havebeensymptomatic(overdiagnosis)
(Gøtzsche PC,Jørgensen KJ.Screeningforbreast cancerwith mammography.CochraneDatabase Syst Rev.2013;6:CD001877.)
Cochranedatabase :
2000pearls inabowl…
...they represent 2000women,40years old andover,screened during 10years.
Screeningis agamble,its consequencesareaquestionofchance…
Onegoldenpearl :1lifeextended byscreening.
10red pearls :10healthy women,with useless diagnosis,subjectedtofutiletreatment.
200whitepearls: : 200women suffer thestressofafalsealarm;they havetoundergo other teststorestorediagnosis;their anxiety may lastforweeks ormonths.
2200women
Screeningdetects alotofsmall tumors whichwould never progress,orwhich would disapear
without treatment.Ifthey had remainedunknown,they would nothaveharm,bother or
kill thepatient.
Another definition ofoverdiagnosisis
discovering tumorsthat would nevercauseany sickness
until thewoman diesforanother reason.
Thatisoverdiagnosis :anunexpecteddiscovery,
caused bymassscreening.
OVERDIAGNOSIS
• Calculation ofoverdiagnosis :excess ofcancersatthewomenscreened /totalnumber ofcancerswhich would havebeendiagnosed withoutscreening(populationwithsame profile,same age).
• Overdiagnosisoccuramong women who takepartinscreening.
• Laststudies (Zahl/Autierandearlier Junod): 50%overdiagnosis=half ofalldetected cancers.
Two errors increase each others :
*radiologic orhistologic images
donotdefine mortal cancerous desease.
*TheHalsted theory,whichdescribeofalinearnaturalhistoryofcancer,quitemechanical,isrefutedbyfacts.
Physicians,patientsandpathologists cannotrecognise who gets overdiagnosed.
Forindividuals,there areonly diagnosis.
Only epidemiologists can detect overdiagnosisbycomparing populationssubmitted toscreenings of
variableintensity.
Studies
• Interval-cancersarenotworse thanbreast cancersdiagnosed intheabsenceofscreening.They donotkillmore,andthey don’t havemoreaggressive clinical andpathologicalfeatures.
• So:ifinterval cancersaresimilar tocancersdiagnosed without screening,andifscreened cancershaveabetterpronosticthan interval cancers,itmeans that some screened cancersarenot-mortal cancers,that would neverhavecaused symptoms.
• Osloexperience,2008,comparison oftwo groupswomen,onescreened,theother onewithoutscreening:22%cancersinexcess =overdiagnosis(only invasivecancerscounted)
• Autopsiesstudies (systematic reviews :40%ofinvasivecancersdetected bysystematic screeningand24%ofalltheinvasivecancerswould beoverdiagnosed.)
• Aplethora ofepidemiological data(Harding,Miller,Bleyer,Zahl,Autier)showsthat,since 1985,progress inthemanagementofbreast cancerpatientshasled tomarked reductions instage-specific breast cancermortality,evenforpatientswith spread desease atdiagnosis.
• Moreover,themoreeffectivethetreatments,theless favourable aretheharm–benefit balanceofscreeningmammography.
• P.Autier :Mammography screening:Amajorissueinmedicine
Anonlinear natural history ofcancer,butaspectrum ofcancers
• theopportunity fordetectionbefore their metastaticdistributionwould be very short.
• These high-staged tumors haveanagressiveandfast evolution,andthey arealready largeatdiagnosis.
• …so these tumors will veryoften be discovered bymammography screening,
• Andthearesmall whendiagnosed because oftheirslowevolution.
• Attheother endofthespectrumarecancerswithgreat metastaticpotential.Theydevelop quickly
• …
• Mostcancersareasymptomatic tumorswhich would remainpainless orwoulddevelop slowly…
Afewofthembecome symptomatic
diseases.
They havealonginfra-clinical period(longresidence timewithout clinical sign in
thebreast)….
...andmetastaseswould be alreadypresent inlymphnodes anddistantorgans when thetumor is detected.Because oftheirshortresidencetimeinbreast…
ld
Two models ofnatural history ofcancerareinconfrontation
Insitucancer
Invasifcancer
Metastatic cancer
death
Some years
Some years
Linear model,
Baseofscreening
Alternativemodel,stemming from facts
Invasivecancer
DeathInsitucancer
Metastase
Cancerdisease
regression Stagnation
Evolutionis notlinear,nor regular,nor systematic
Insitucancers/interval cancers
• Mammography hasahighsensibility forinsitucancers.
• Screeningusually detects atypicepithelial anomaliesorafewagressivetumors,like low stageCIS.
• Buttotreat thesame way insituandinvasivecancersdonotdecreaserecurrences orbreast cancermortality .(StevenNarod,study Toronto2016)
• Taking invasivecancersandCISintoaccount endsinoverdiagnosisaround30oreven 50%.
• Before screening,less than 5%ofallbreast cancerswhere CIS.Whenparticipationinscreeningis significant,15à20%ofalltumors areCIS.
• Incontrast mammography haslowsensibility forsome agressivecancerslike the‘triplenegative’.
• Invasivecancersdetected byscreeningareclinically andhistologically less agressivethaninterval cancers.
• Screened cancerskill less than isinterval cancers.
• So:thefact that abreast cancerwasdetected bymammography screeningis indeed agood-pronosticfactor.
Consequences ofoverdiagnosis
Judicial effect :physician condemned for
"missing"asmall cancerthat would
havehad novitalimpact
Def.:
Nocebo effect occur when anticipationofanunwanted effect makes this
unwanted effect happen.Thesubjectwaits foranegative event defined bysocial,media,professional orpopularmessages,andthis event happens.
Nocebo effect doesn’t affecteverybody.Itvarieswith mentalstate,internal
imaging andrelationwith theexternalworld.
Italso depends onself-analysis capacity,andthesocialcontext.
Suggestionsare:messagesandnegative attitudesfrom medical staff,
autosuggestionsby:
·individual conditioning beliefs,·« doctors whitecoat effect »,
.Collectivesymbolic representations.
Nocebo effect SandersPeirce(american philosoph)Ourconvictionscan be imperative,astheoneaccording to"themoreacanceris taken intime,themorewe havechancetobe cured »:*bytenacity (repetition),even ifpersisting inthebad faith,*byapriori(that mustbe true,even ifit is notdemonstrable)*byargumentofauthority releasingusfromdoubt andfrom reflection,*byscientific method,allowing criticism ofmethod andresults,butintellectually moredemanding.
Chronical stressbecause ofterrorofcancer,maintained bythe
medical profession,relieved bymedia.
Painful,stressful examinations,alarming expectationsofthe
results every 2years,falsealarms,andmedical escalation.
Trans-generationnelnocebo-effect
(convictionoffamilialdisease passed ontodaughters,grand-
daughters.)
Physicalandpsychic impactsof:• Preventive breasts removal,
sometimes demanded bywomen,
• Excessiveradiotherapy andchemotherapies.
• Complicationsofsurgicaloperations.
• Radio-inducted cancersthrough repeatedmammography andradiotherapy.
Atleastastresseffect
Physicians unconsciously noceboeffect byusing certainwords,silences,acts orgestures :
diagnosis becomes aself-fulfillingprophecy,announced bythe
physician intheobsessionofthe« righttoknow »enshrined inlaw.
Anxiety is passed onby:
*roughverbalsuggestionofthephysician ("Ifyou donotfollow my
advice,cancermay kill you ")
*theusual practicejustifying theact(screeninghabit)
*lack ofempathy with patients
*fear felt byphysicians himself
Thewill todowell andto"savelives"may leadto
theopposite
Theterror ofdisease inoursocieties leadstoovermedicalisation.Itmakessick many healthy people(likewomen 50-74years old)
Socialfears,socialrepresentations ofcancerdisease.
Thesocialrepresentations ofcancerdistort theconceptionsofpeople
aboutthis disease,alteritsperception.They influence
therapeutic strategies andpublichealth policies.
Themalignant cell is saw asadisobedient sociopath,anexpansionist enemy who
catchesalltheresources ofthebody.
Malignant cell is considered adelinquent,aninsane,adrug-
addict andamigrant:itcondensesour socialfears
Byrefering tosocialdangers,we leavescientific statement andwe setoutto
judge,sentenceandexclude,andwe castfault andshame tothepatient.
Military vocabulardemand war action
against cancer,butthisanalogy is inadequate.
War supposesthedestructionoftheenemy,butwith theageing ofthepopulation,cancersaregoingtoincrease.
Socialfears,socialrepresentations ofcancerdisease.
Amilitary strategy that aims toeliminate alltumors will increaseovertreatment,with heavy morbid
consequences.
Istheresearcher inoncologyjust anobedient serviceman?
Where is theintellectualadventure which questionsthepreestablished theoreticalmodels?Where is theambitiontodiscover ?
Thepatient is notasoldier takingorders from atopmanagement,heis notacancer-hero,andeven ifheis fighting,there is noreason to
accusehim ofsurrender ifhe fails.
Other cancermodels exist,fundamental research mustquestionthenatural history
ofcancer.
Therearenonmilitary ways tomake diseasefitinthepersonal bibliography ofthepeople,tofacepossiblerecurrences andchronicdisease,which may disrupt onelife.
LesfemmessontPlusvigilantesqu’autrefoissurlesmodificationsdesseins
Fortheamericanphysician andmethodologistD.Sackett,thiskind ofpreventivemedecine is :
A.Assertiveonhealthy individualswithout anysymptom,tellingthem what todotoremain healthy;
B.Presumptuous,claiming that itsinterventionswillgenerally make betterthan worst tothose whosubscribe toit;
C.Tyrannical,doingeverything toexercise itsauthority,through :
• publicfear campaigns• Mediacoverage• Public« education »• Collusionwith pharma
industry.
LesfemmessontPlusvigilantesqu’autrefoissurlesmodificationsdesseins
TodayCurrent treatments aremoreeffectiveagainst
cancer.
Cancerdoes notevolve inalinear,mecanical way.
Letusnotminimize theunwanted effects:*overdiagnosis/overtreatment*falsealerts
*radio-inducted cancer
Itis notethical tousefear ofthecancer,oremotional argumentstocompel women.Neutral,honest,understandable informationenable women tochoose freely.
Screeningmustbeexplained withoutexageration,with thecontroverse,withabsolute risk,andtherealbalancebenefit/risks.
Her bodybelongs
toawoman.
She havearight
tosay yes ornoto
breast cancer
screening,andto
make personal
choice.
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