jcoloproctol(rioj).2015;35(1):1–2
w w w . j c o l . o r g . b r
Journal
of
Coloproctology
Editorial
Metachronous
rectal
cancer
after
surgery
for
familial
adenomatous
polyposis:
what
should
we
expect?
Familial adenomatous polyposis (FAP) is an autosomal dominant inherited syndrome characterized by multiple adenomatouspolyps(predisposingtocolorectalcancer devel-opment)andnumerousextra-colonicmanifestations.Itmay affectupto8per1000persons.Ifnottreatedby prophylac-ticcolectomy,FAPpatientswillhaveanestimated100%risk ofdeveloping colorectal cancer (CRC).The majority ofFAP patientswillbeaffectedinacontextoffamilialhistory. How-ever,almost30%mayhavea“denovo”mutation.ClassicFAP anditsattenuatedform(AFAP)derivefromgermlineAPC (ade-nomatouspolyposiscoli)genemutations.
Inanidealscenario,themajority(ifnotall)ofFAPpatients should undergo surgery as result of effective surveillance, beingoperatedon whilestillasymptomatic.Therefore, the most important objective to be accomplished is CRC pre-vention. Surgery represents the sole means of preventing CRC,throughrestorativeproctocolectomy(RPC),orthrough totalcolectomywithileorectalanastomosis(IRA).Apartfrom obvious, it is widely known that RPC is associated with increased early and late morbidity. On the other hand, it ismoreeffectivethan IRAtopreventoccurrenceand mor-tality from rectal cancer in patients with FAP undergoing prophylactic surgery. Notwithstanding, making the choice betweenRPCand IRAcontinuesamatterofdebate. There-fore, the paper published by Stevanato Filho et al. in the presentissueofJCOLrepresentsaveryimportant contribu-tionaboutdefiningsurgicaloptionsinFAP.Inaretrospective single-institutionalanalysisof22patientswithclassicFAP,the authorsreportedcomplicationsoccurringin34.3%,although withnomortality.Ultimately,theincidenceofrectalcancer afterRPCandafterIRAwas2.3%and18.8%,respectively.Given theseresults,whatshouldbetheexpectedCRCoccurrence forFAP patients undergoingsurgery after genetic counsel-ingandregularclinicalfollow-up?Itshouldbewarnedthat a crude answer may not be available at the end of this editorial.
IRAiscurrentlyrecommendedforpatientswithfew rec-talpolypswithhighriskaversionandalsoforfemalepatients willingtobepregnant.IRAisassociatedwithfavorablesurgical andfunctionaloutcomesandametachronousrectalcancer rateoflessthan 15%inthepost-RPCera.1,2 Itisestimated
thatafterIRA,metachronousrectalcancerriskisassociated with the length ofpostoperative follow-up and the site of APC mutation.3,4 It isalsohypothesizedthat bad selection
criteriawouldaccountforarateofmetachronousrectal can-cerafterIRAabove15%.Nevertheless,maybebadselection criteria are not the major cause for a possibly high inci-denceofrectalcancerafterIRA.Perhaps,forasubgroupof patientswithmanifestindicationsofIRA,itwillbe unfeasi-bletopreventtheoccurrenceofmetachronousrectalcancer withoutadditionalinformationderivedfrommutation anal-ysis. Maybe this is a reasonwhy, during the last decades, RPCprogressivelyturnedouttobethemostcommon oper-ation despite its surgical morbidityand need fortechnical expertise.
Ithasbeenwell establishedthatthereisalinkbetween thesiteofmutationoftheAPCgeneandsomefeaturesofthe phenotypeofFAP.Thisistheso-calledgenotype–phenotype correlation. What isthe impactfrom mutationanalysison surgical decision for FAP patients? In a study comprising data from four national polyposis registries, according to previously described genotype–phenotype correlations, 475 patientsweredividedintothreegenotypegroupspredicting attenuated,intermediate,andseverepolyposisphenotypes.5
2
jcoloproctol(rioj).2015;35(1):1–2However,howdoes thisresultcompare toclinical decision makingwithoutmutationanalysisremainsunknown. There-fore, the results publishedby Stevanato Filho et al. inthe present issue may represent evidence toward a need for broader use of genetics-based surgical decision. Unfortu-nately,untilthere,mutationanalysiswillremainunavailable tomanysurgeonsandinstitutions.
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1.SmithKD,Rodriguez-BigasMA.Roleofsurgeryinfamilial
adenomatouspolyposisandhereditarynonpolyposis
colorectalcancer(Lynchsyndrome).SurgOncolClinNAm.
2009;18:705–15.
2.BülowS,BülowC,VasenH,JärvinenH,BjörkJ,ChristensenIJ.
Colectomyandileorectalanastomosisisstillanoptionfor
selectedpatientswithfamilialadenomatouspolyposis.Dis
ColonRectum.2008;51:1318–23.
3.BertarioL,RussoA,RadiceP,VarescoL,EboliM,SpinelliP,etal.
Genotypeandphenotypefactorsasdeterminantsforrectal
stumpcancerinpatientswithfamilialadenomatous
polyposis.HereditaryColorectalTumorsRegistry.AnnSurg.
2000;231:538–43.
4.CamposFG,PerezRO,ImperialeAR,SeidVE,NahasSC,
CecconelloI.Surgicaltreatmentoffamilialadenomatous
polyposis:ileorectalanastomosisorrestorative
proctolectomy?ArqGastroenterol.2009;46:294–9.
5.NieuwenhuisMH,BülowS,BjörkJ,JärvinenHJ,BülowC,
BisgaardML,etal.Genotypepredictingphenotypeinfamilial
adenomatouspolyposis:apracticalapplicationtothechoiceof
surgery.DisColonRectum.2009;52:1259–63.
SergioEduardoAlonsoAraujoa,b,c,∗,
FábioGuilhermeCasertaMarysaeldeCamposa,d,e
aMedicalSchool,UniversidadedeSãoPaulo(USP),
SãoPaulo,SP,Brazil
bHospitalIsraelitaAlbertEinstein,SãoPaulo,SP,Brazil
cAssociac¸ãodeColoproctologiadoEstadodeSãoPaulo(ACESP),
SãoPaulo,SP,Brazil
dColorectalSurgeryDivision,DepartmentofGastroenterology,
MedicalSchool,UniversidadedeSãoPaulo(USP), SãoPaulo,SP,Brazil
eSociedadeBrasileiradeColoproctologia(SBCP),
RiodeJaneiro,RJ,Brazil
∗Correspondingauthor.
E-mail:[email protected](S.E.A.Araujo).
http://dx.doi.org/10.1016/j.jcol.2015.01.008
