Objective:Weinvestigatedthecorrelationbetweenthenumberofcirculatingtumorcells(CTCs)andwholebodymetabolictumorvolume(WBMTV)measuredby18F-fluorodeoxyglucose(FDG)positronemissiontomography/computedtomography(PET/CT).TheaimwastoevaluatethevalueoftheincorporationofCTCnumberandWBMTVintheprognosticpredictionofstageIIIsmall-celllungcancer(SCLC).Methods:Onehundredandtwenty-ninepatientswereenrolledinthisstudy.Allpatientsweretreatedwithfourcyclesofaplatinum-basedregimenandconcurrentchestirradiation,followedbyprophylacticcranialirradiation.BloodsamplesforCTCanalysiswereobtainedfrom112patientsbeforetheinitiationofchemotherapy(asabaseline),aftercycle1andaftercycle4.CTCsweremeasuredusingtheCELLSEARCH?system.ThepatientsunderwentpretreatmentFDGPET/CTWBMTV,whichincludedallmalignantlesions.TheSpearmanranktestwasusedtodeterminethecorrelationamongCTCcounts,WBMTVanddiseasestage.Overallsurvival(OS)andprogression-freesurvival(PFS)curveswereproducedusingtheKaplan-Meiermethod,andsurvivaldifferencesbetweengroupswereassessedbythelog-ranktest.Results:ThenumberofCTCsatbaselinedidnotcorrelatewithWBMTVbeforetheinitiationoftherapy(P=0.241).ThenumberofCTCsatbaselineandtheWBMTVbeforetheinitiationoftherapywereindependentrelevantfactorsforPFSandOS.Thesubgroupanalysis(GroupA:CTCcount>19.5andaWBMTV>266.5cm^3;GroupB:CTCcount>19.5andaWBMTV≤266.5cm^3;GroupC:CTCcount≤19.5andaWBMTV>266.5cm^3;GroupD:CTCcount≤19.5andaWBMTV≤266.5cm^3)showedthatthedifferenceswerestatisticallysignificantinthemedianPFS(GroupAvs.D,P<0.001;GroupBvs.D,P=0.018;GroupCvs.D,P=0.029)andinthemedianOS(GroupAvs.D,P<0.001;GroupBvs.D,P=0.012).Conclusions:CTCnumberandWBMTVarerelatedtoprogressionanddeathinpatientswithSCLC.TheincorporationofCTCnumberandWBMTVscanscanprovideadetailedprognosticpredictionforSCLC.
