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TheFirstInternationalInvasiveLobularBreastCancerSymposiumwasheldinSeptember2016attheUniversityofPittsburgCancerCenter.ThesymposiumwaschairedbyDr.SteffiOesterreichandDr.NancyDavidsonoftheUniversityofPittsburghCancerInstituteandDr.OttoMetzgerofDana-FarberCancerInstituteandattendedbyover130researchers,cliniciansandincludedlobularbreastcancerpatientsfromaroundthecountry.

AstheLobularBreastCancerPatientAdvocateswhoattendedthisconference,wearewritingthiswhitepapertosharethemainfindingsofthemeetingandaskyoutojoinusinpromotinginvasivelobularbreastcancerasadistinctcancerthatrequiresrefinementsinscreening,patientcare,enhancementsinpatientandprovidereducationandsubstantivemeasurestoaccelerateresearch.

Thisconferenceunderscoredthatinvasivelobularbreastcancer(ILC)andotherlobularbreastpathologies(suchaslobularcarcinomainsitu,LCIS)areunderstudiedandthatcurrentstandard-of-carebreastcancertreatmentsandprotocolsmaynotalwaysbethebestoptionforpatientswithlobulardisease.Specifically:

A) Invasivelobularbreastcanceristhe6thmostfrequentlydiagnosedcancerofwomenintheU.S.with26,000to34,000newcasesdiagnosedayear.Itisthesecondmostcommonhistologicalsubtypeofbreastcancer,comprising10%to15%ofallbreastcancers,andimpactsmorewomenthancancersofthekidney,brain,pancreas,liver,orovariesaswellasleukemiaorlymphoma.(2013ACSSurveillanceResearch)

B) WhileILCisfrequentlyassociatedwithagoodinitialprognosis,recentretrospectiveanalysessuggeststhatoveralllong-termoutcomesofILCmaybeworsethanthosestage-matchedtoductalbreastcancer(Pestalozzi,JCO,2008;Engstrom,Histopathology,2015;Adachi,BMCCancer,2016).

C) ILChasspecificmolecularfeaturesdistinctfromductalbreastcancerwithuniquesubtypesandvariants(McCartReed,BreastCancerResearch2015;DabbsD,BreastPathology,Elsevier).ThehallmarkofILCisE-cadherinloss.(Ciriello,Cell2015)Histologically,ILCoftenformsadistinctsingle-filepattern.

D) ILChasdifferencesinpresentationandbehavior,includingphysicalfindingsofthickeningcomparedtothemorecommon“lump”feltinductalcancers,andatendencytometastasizetouniquelocationsincludinggastrointestinal,peritonealandovarian

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E) CurrentimagingtoolsarelessreliableforearlydiagnosisofILCanddetectionoflobularmetastaticdisease.Givenitsanatomicalgrowthpatterninbreasttissue,itisoftenoccultinroutinemammogramorotherscreening,resultinginlaterstagediagnosis.ImagingprotocolstodiagnoselocalordistantrecurrenceofILCcanalsobeinadequate.(Pestalozzi,JCO,2008;Engstrom,Histopathology,2015;Adachi,BMCCancer,2016)

F) Thereisincreasingevidencethatstandardofcarechemotherapyandendocrinetherapytreatmentscurrentlyequallyappliedtolobularandductalbreastcancersmayhavedifferenteffectiveness.(Metzger-Filhoetal,JCO2015;Delpech,etal.BrJCancer201323299541;Barroso-SousaR,Metzger-FilhoO.TherAdvMedOncol.2016)

Despitethesefundamentaldifferencesindiseasetraits,invasivelobularbreastcancerandInvasiveDuctalBreastCancerareoftentreatedwithsimilarprotocols.Webelievethatincreasingourknowledgeaboutthisuniquebreastcancersubtypepresentsanopportunitytoimproveallaspectsofthisdisease,fromdiagnosisthroughtreatmenttofollow-upcare.

Assuch,weaspatientsareinterestedinworkingtoimprovethefollowingaspectsofILCresearchandpatientcare:

• ExplorereliablescreeningandimagingtoolstoidentifyearlystageandmetastaticILC.

• Encouragecollaborationamongresearchersfromdifferentinstitutionswithdifferent

expertisetobetterunderstandtheuniquemetastaticbehaviorofILC,characterizeILCmetastasisandbetteridentifythesubtlesignsofrecurrence.

• AccelerateresearchintothemolecularalterationsandgenomicdifferencesofILCthatmightenablefuturetargetedtherapies.

• Improvepatienteducationtoprovidebetter,morecomprehensivesupportfor

patientswithILC.

• Re-analyzeexistingclinicaltrialdatasetsthatcombineallestrogenpositivecancerstoevaluatedifferencesbetweenDuctalandLobularbreastcancers.

• Conductclinicaltrialstobetteridentifydifferencesinstandardofcaretreatment

betweenILCandDuctalcancers,andassureinclusionofpatientswithILCintoalltrials.

• IntegrateadesignationforILCwithinmedicalrecordsandeducatemedicalprofessionalsontheuniquepresentationsofILCcomparedtoductal,especiallyatconferencesandprofessionalmeetings.

• DesignategrantfundingspecificallyforILCresearchtofacilitatemoreILCspecific

studiesandclinicaltrials.

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TheFirstInternationalInvasiveLobularCancerSymposiumhighlightedtheneedtomakesubstantivechangesindiagnosisandfollow-upcareforthethousandsofpatientslivingwithlobularbreastcancer.TheconferencealsosuggestedthereareopportunitiestoresearchrefinementsintreatmentstobetteraddresstheuniquetraitsofILCgiventhedifferencesinbiology,pathologyandetiologyoflobularbreastcancers.AsthepatientswhoattendedthefirstsymposiumandcomprisethefoundingSteeringCommitteeoftheLobularBreastCancerAlliance(LBCA),westronglysupportmoreresearchandclinicaltrialstoimproveourunderstandingofthisuniquebreastcancersubtypetobetterinformtreatmentandsupportpositiveoutcomesforpatients.Reviewabstracts,slides,apatientQ&AvideoandotherresourcematerialfromtheFirstInternationalLobularBreastCancerSymposium.