ATYPICAL RESPONDERS LANDSCAPE REVIEW ∙ OCTOBER, 2017 32 TABLE 1 CATEGORIES AND TERMS RELATED TO ATYPICAL RESPONDERS STUDYOR INSTITUTE QUALITATIVEDEFINITION METRICS/QUANTITATIVECRITERIA Universityof Wisconsin- Madison’s Exceptional Survivors Study Refersto“exceptionalsurvivors”asMBC patientswhohavelivedanunusuallylong time sincetheirfirstbreastcancerdiagnosis(early stageordenovo)tothecurrentdate.The underlyinghypothesisrelatingtothisdefinition isthatearlystagepatientshavehadmetastatic diseaseallalong,buttheirtumorcellshave remaineddormantorextremelyslowgrowing, andmetastaticdiseasehasbeenclinically undetectable.Incontrast,theMBCAdefines exceptionalsurvivalasthetimefromthe advancedstagediagnosistothecurrent date. ForMBC patients withER+disease: •Duration sinceearlystageordenovobreast cancerdiagnosis (overall survival) 10+ years ForMBC patients withER−disease (the studywilldistinguishbetween patients withHER2+vs.TNBC afterenrollment): •Duration sinceearlystageordenovobreast cancerdiagnosis (overall survival) 5+ years Editorial: Subbiahand Subbiah(2015) An“exceptionalresponder”isapatient who obtains“acompleteresponse,showing no radiographicevidenceofthecancerwhere previouslywidelymetastaticcancerwas noted”[8]. • Not quantifiable •Doesnot capturerapidprogressors Editorial:Chau and Lorch(2015) Described“exceptionalresponders”as“a minorityofpatientswithcancerwhorespond todrugsinanunexpectedandoftendramatic degree”[9]. •Not quantifiable •Doesnot capturerapidprogressors Short report: Levinet al.(2015) “Exceptionalresponders”arethosewith a “highlydurable(≥5years)orongoingclinical response”[10]. •Highlydurable(≥5 years) orongoing clinical response •OnlypertainstothechemotherapyunderstudyXeloda® (capecitabine) •Patientsmaybeheavilypretreated •Doesnot capturerapidprogressors TABLE 1 CONTINUED